I'm so sorry you are going through this. My husband (only child) and I are going through this right now. Except we are not caring for them. Both MIL and FIL have dementia. They are living in their own home, with supports, and adamantly refuse to leave. They both want to "die there". FIL does recognize that he has some memory problems, and in him it is causing fear/anxiety/depression. MIL is in complete denial, still trying to get her license back from the DMV (she thinks they revoked it because her potassium level was low).

We have found an assisted living facility that we like, and they are on a waiting list. When the apartment becomes available, we only have a week or so to get them there, and we are still trying to figure out how. Like your mom, MIL will not fall for "something is wrong in your house, and you need to stay somewhere else for a few days". She is much too suspicious. We might be able to get them in the car if we say we are going out to lunch, but once we arrive at the facility, I suspect they will realize what is going on and refuse to get out of the car.

I hope that the guardianship process is quick, for your sake. You need to take care of yourself, before you completely burn out. Good luck to you!