I went through this with my mom. There’s more known about this condition now. If you can listen to podcasts, I’d suggest listening to Peter Attia’s interview of Francisco Gonzalez-Lima, Ph.D. I wish I’d known at least some of this back then.

On the interview, Attia mentions that there’s a lot of information in “show notes” if you subscribe. That’s probably the best way to get all the info mentioned in written form — but Gonzalez-Lima has published quite a few scientific studies. Here’s a search for all of them on PubMed.

I’m so sorry you’re going through this. About the only positive I got was that I was able to mourn my mom with her — but your mom might be past that point now. Hugs! (so long as you don’t consider that creepy)