Hello Boldhero: I noticed this is your first post here on PC. Welcome to Psych Central.

You wrote that your sister's god obsession has been going on for years & you can't communicate with her anymore. Then you asked what others would do. Personally I just wouldn't communicate with her anymore. I'd send her an e-mail, or a text, or whatever, & tell her if-&-when she's able to communicate regarding something other than her god I'd be glad to communicate further. But until that day comes I will no longer reply to her messages. That's it... no contact. (This is what is referred to as personal boundaries.) That may or may not be a solution you're comfortable with. But that's what I'd do.

I hope you find PC to be of benefit.

P.S. Here are links to 6 articles, from Psych Central's archives, on the subject of personal boundaries:

The Importance of Personal Boundaries

What Are Personal Boundaries? How Do I Get Some?

Tips on Setting Boundaries in Enmeshed Relationships

When People Cross Your Boundaries

5 Ways to Maintain Boundaries with Difficult People

https://blogs.psychcentral.com/imper...ur-boundaries/