Another way to look at it is that maybe you need to respect his decisions instead of trying to control how he lives his life. Everyone has to make their own choices and live with the consequences. You can't fix what you think is wrong with his life anymore than he can fix what he thinks is wrong with your life.

He is the only one who decides how he lives his life.

True friend is uncommon, not to be found by common man.

TYhink of yourself and what your needs are what you want he only seems concerned with himself.

He needs to live his own life, just as much as you need to live your own life.

My guess is that he cannot abandon his own irrationality any more than you can abandon your own rationality.

He may be too driven by his own fears to question what he has been told by his theology teachers. It seems that religious trauma, such as he may have experienced, results in catastrophic damage to the pre-frontal cortex of the human brain, so the irrationality of "My god is the real god, all other gods are false gods" would not be apparent to him.

Care for yourself. Know that there are others out there. Be kind to yourself, and be patient.

You may have to leave without his permission. Based on what you've told us, he's not taking you seriously.

You can't make him choose he must do it himself

He is living his own life, the life he chose...