I just have more and more trouble believing that actual functional adults believe in this crap. My mom is one of them, and I keep boggling at her ideas.

Like, if she misplaces her keys then finds them, she thanks her god for finding them for her. Never blames it for hiding / losing the keys, of course. She's absolutely confident that her beliefs match what her god wants, despite hers being picking and choosing from the various holy books. Her church isn't quite mainstream for her religion. Her beliefs don't quite match her church. But, of course, she's right.

A family friend of hers is dying of dementia. He is non-verbal and can no longer feed himself. Soon he'll have to be on a feeding tube because he'll no longer be able to swallow. This, of course, is her god's plan. He wants a nurse to have to handle his waste and feed him with a tube. But, naturally, her god doesn't want those same medical professionals to assist someone in dying with dignity.

She also literally believes stories that are less believable than fairy tales. Apparently some holy person didn't eat or drink for years! This other one healed people! Another one predicted future events! We know these are true because other people from that religion verified it, and if you can't trust people of her religion, who can you trust?

How can an adult stop believing in things like Santa Claus and underpants gnomes, but keep believing in this religious stuff?