Why would did your mother continue to see this doctor if that's what his diagnosis was? Secondly, why did you allow that continue on and not find another doctor who wasn't an idiot? I'm not attacking you or anything, but even as someone who believes in God myself, I wouldn't allow a member of my family to see someone who wasn't going to give them the best possible care.
me and my sister were totally against this doctor, but it wasn't legally our call. My father believed in her psycho crap. The exorcism pretty much killed her so there wasn't much point in it after that. I do remember she didn't want to do anything like that so they tricked her letting her think it was for something else and they wouldn't let her leave when she wanted to leave, we know that from phone calls made to my father while this was going on. They did this to her for about half a day while we were trying to figure out where the hell she was. Before she got sick, my father wasn't really a christian. didn't go to church and didn't read the bible or any of that. He was desperate for something when this happened and the good doctor was right there to exploit that.
Me and my sister were also told by the doctor that part of why my mother was dying was because we were not christian and that the only full way to save her was for us to believe. She even gave us bible assignments

It got so strange at one point, we had to hide things, recover from the garbage, that the doctor had deemed evil and needed destroyed. She toured the house and started picking out things that were evil and had to go... WTF... One of the things actually being a christian book about marytrs from the 1600s lol... I guess it looked evil... She's not alone either. There are others like her, she learned the crap from a church here, I think born again type of stuff. We're still occationally reminded today that if we don't become Christian, we'll never get to see loved ones we've lost again... sick way of converting people... I don't think this kind of stuff is rare. I think more christians are like this and some like to admit.