Conversation ends with an eye roll and dispear. How do you reason with someone like that.
You don't. You leave it alone. They have the right to their beliefs just as you have the right to yours.
My mother is still a witness. I wouldn't dream of laying into her with whatever this week's forum hobbyhorse is. As long as she is happy that's fine by me.
We talk about the kids, holidays or whatever. If I was constantly attacking her faith then it would make for a strained relationship and why on earth would I want that with my mother?