I lurk a ton on TRP but this is a throwaway because of the identifiable info in the post; mods excuse my deviance if possible.

TLDR; my mom probably has OCD (subtype scrupulosity), has slowly chipped away at my dad’s natural alpha frame with constant shit tests, what should I advise him to do

My dad was naturally alpha in his younger days as he was an Indian male. His wife had a nursing degree but he wasn’t very educated so there was a natural imbalance once he got married. It was a traditional arranged marriage and as such had traditional power dynamics in the beginning.

My mom was a very religious catholic and converted to some crazy brand of Pentecostalism before she got married. As time went on and my dad was absent due to his business, my mom would start to hang out with similar like-minded religious nut-cases in town who are very brainwashed yet convincing. She got more and more illogical and basically would spend her entire time praying obsessively. I’m pretty sure she has a mental problem.

At this point, she doesn't listen to what my dad says at all. She goes around traipsing around town with her religious friends who basically undermine any semblance of a normal family life in our house.
For example, today she went to work at 7:00 AM, went to one person’s house to “pray”, then went to another person’s house to “pray” for their cancer. She then went to sleep immediately after coming home at 9:00 PM. The sad thing is that this is typical. If she isn’t out doing thisk she’s at home yelling/singing or acting crazy.
Seeing all this, my dad gets angry and then she calls him demon-possessed. If he goes along with it and is nice, she rationalizes it as “God has changed him”. Basically, her hamster is a born-again bible thumper. You can’t win. From what I can tell, my mom hasn’t cheated on him (except maybe with Jesus), and their sex life seems to be non-existent.

Her shit tests are endless as well. I told my dad about ignoring, or agreeing and amplifying, but I feel he lacks the mental DGAF attitude to execute. He just gets pissed, as I think any man would when your frame is under constant attack. He’s also definitely not going to flirt with other women to increase dread or get a divorce, both options which I have suggested.

Given all these pre-conditions, how does my dad regain a proper male-female dynamic in the house per TRP principles? I am at a loss on how to help.