I used to go to a small Presbyterian church and even became a member. Now I am a closet atheist (my wife knows) and I really want to remain that way until I am comfortable with sharing my non-belief. I moved down the street and I don’t go to that church anymore. My ex-pastor is good friends with my brother in law and the pastor keeps asking how I’m doing and if I found a church.
Tell him you prefer that he no longer asks you that, as you are happy with your decision to leave his church and in no need of establishing with another church.
Does he phone you? Block his number. See you in the grocery? Excuse yourself, no reason needed. Stop you on the sidewalk? Same. Come to your home? Ask him to please stop visiting, as you have no business with him (religion is his "business" ).
Do you speak with your brother-in-law? Might be good to let him know that the pastor's contact is not welcome.
You made a choice, and have no obligation to share your values with anyone, but you may want to consider how the "truth will set you free!"
 tinkercreek
                                                
                                                Level 8
                                                Dec 18, 2019
                                            
                                                
                                                    tinkercreek
                                                
                                                Level 8
                                                Dec 18, 2019                                            
                                        Just tell him yes, you did find another.
 nvrnuff
                                                
                                                Level 8
                                                Dec 18, 2019
                                            
                                                
                                                    nvrnuff
                                                
                                                Level 8
                                                Dec 18, 2019                                            
                                        Yes. An evidence-based belief system.
A shouting match never hurts. Tell him that you are beginning to feel harassed and you'll not be harassed in this way. If he comes to your home,
it's trespassing, if on the street it's soliciting/stalking. An injunction/restraining order may help should it go that far? 
Failing that, a good old fashioned sock in the face might send the right message.
 NovaHEX
                                                
                                                Level 3
                                                Dec 20, 2019
                                            
                                                
                                                    NovaHEX
                                                
                                                Level 3
                                                Dec 20, 2019                                            
                                        So your BIL thinks he's doing you a favor by passing on the pastor's concern? OMG, the problem isn't with the pastor, but with your BIL. You need to tell THAT dude that you have no interest in what the pastor wants, and "why are you asking me, anyhow?"
 Ellen-SoCal
                                                
                                                Level 5
                                                Dec 19, 2019
                                            
                                                
                                                    Ellen-SoCal
                                                
                                                Level 5
                                                Dec 19, 2019                                            
                                        This!
You could tell him you have found St. Mattress to be more supportive.
 NoMagicCookie
                                                
                                                Level 8
                                                Dec 19, 2019
                                            
                                                
                                                    NoMagicCookie
                                                
                                                Level 8
                                                Dec 19, 2019                                            
                                        I found the best thing to do is the reverse: engage in deepest longest most boring whiny nonsensical nontopical meandering conversation EVERY time he asks you. Keep him there for hours, in a standing position, with no breaks, if he tries to leave try to prolong the conversation till he absolutely insists he has to leave.
I promise you he will not dare ask you anything ever again. 
 MakeItGood
                                                
                                                Level 7
                                                Dec 19, 2019
                                            
                                                
                                                    MakeItGood
                                                
                                                Level 7
                                                Dec 19, 2019                                            
                                        "I'm doing just fine, I am completely centered, happy and content. For the moment I do not need any kind of help or guidance. Should I needed it you'll be the first to know"...
 Merseyman1
                                                
                                                Level 9
                                                Dec 18, 2019
                                            
                                                
                                                    Merseyman1
                                                
                                                Level 9
                                                Dec 18, 2019                                            
                                        This is your brother in laws problem, not yours. Just tell your brother in law that you don't want to hear about your ex-pastors questions of how you are doing.
 afrogonalog
                                                
                                                Level 5
                                                Dec 18, 2019
                                            
                                                
                                                    afrogonalog
                                                
                                                Level 5
                                                Dec 18, 2019                                            
                                        Threaten him with prosecution for harassment, that was what I had to resort to in order to get the LDS off my back.
 LenHazell53
                                                
                                                Level 9
                                                Dec 18, 2019
                                            
                                                
                                                    LenHazell53
                                                
                                                Level 9
                                                Dec 18, 2019                                            
                                        By the title I thought of a cease and desist letter, but you are more complicated. Good luck.
 Beowulfsfriend
                                                
                                                Level 9
                                                Dec 18, 2019
                                            
                                                
                                                    Beowulfsfriend
                                                
                                                Level 9
                                                Dec 18, 2019                                            
                                        Have you told your brother in law that you don't want to hear from him any more? When he asks you, how about saying I'm fine, and no. It is pretty benign. Do you see your BIL every day? Is he constantly harassing you with these questions? Actually, it isn't the worst thing to have to deal with. Just blow him off.
 Wisewoman3
                                                
                                                Level 7
                                                Dec 20, 2019
                                            
                                                
                                                    Wisewoman3
                                                
                                                Level 7
                                                Dec 20, 2019                                            
                                        Tell him you belong to round church so the devil can’t trap you in the corner.
 atheist611
                                                
                                                Level 6
                                                Dec 19, 2019
                                            
                                                
                                                    atheist611
                                                
                                                Level 6
                                                Dec 19, 2019