I have full meltdowns.
Not long ago I found great relief after having watched Anderson Cooper's documentary with his mother Gloria Vanderbilt titled "Nothing left unsaid".
It is poignant and so beautifully done, nothing is withheld.
One of the lines that has stuck with me, and it does seem to me that Anderson has had access to a great therapist is :"There is no answer for why, there just is" (paraphrasing).
That line alone has brought me great comfort.

I'm sorry for you loss.
L

The same way other Atheists do....With the support of your friends and relatives, by crying whenever/wherever the memories engulf you, by seeking help from grief groups, by yelling and screaming if that helps you to exit out the pain, by helping others who are going through the same, by getting involved in organizations that deal with your stepmother disease and helping to find a cure.....

I lost my partner to breast cancer in 2013, this was some of my writing about that.

I think that grief is probably the most peculiar of all human experiences.

Some days I find myself crying over nothing, for no reason, and then other times feel guilty when I am happy.

Seems like after a few million years of development that we would have found a better way to transit the death of those we love, but I just make it up every day as I go fumbling and lost like everyone else.

In the end, maybe that is the very best part of the experience, because grief does serve to remind us of our own humanity and underscores just how precious life truly is.

Thinking about all the ones I have loved and lost, and all those around me suffering with their grief.

Know that you are loved.

Know that life is filled with joy and wonder.

Know that one day the pain will end and you will wake up, filled with bliss and grateful for the experience.

It's unfortunate, but while I'm saddened by the loss due to medical illness, I'm even more relieved for the one I lost. I don't know what lies beyond, but, like what you used to embrace for comfort (why be ashamed of that?), I cope by believing my loved one has shed the ills of this existence and has evolved to another stage of human evolution...if we're even remotely still "human".

It smiles my face believing this was only the beginning and despite how they were lost, they're onto the next phase.

Not everything can be proven to satisfy our preference for logic and reasoning...I know I long to understand it all. 'til then, cope in the way that makes you feel better...anyone who tries to reason you to feeling ashamed, is likely the one nobody ever played with as a child.

Grieve as it comes naturally to you.

Losing someone dear to you is very hard and it takes sometime for it to heal. All you can do now is to accept reality in order for you and your family to have a peaceful mind facing tomorrow without the person you loss. Life is so unfair, I know, but as a nonbeliever we must stand strong especially during moments like this and I'm very sorry for your loss.

I listen to good music ,meet my good friends and try to do the things I want to do while I,m here,read books ,whatever ..life is fleeting ,enjoy it..

I'm sorry about your stepmother's death and the grief you feel. When you think back on the comfort religion provided in these circumstances, what in particular was comforting? I think if you can isolate which needs were met by religion, you may be able to find other ways to provide similar solace.