I am glad that it is a good place - that must make it easier. We just moved my mom up here from where she has and the new place doesn't have a frail care facility. Her worst fear is Dementia. My gran got it and mum looked after her until she couldn't. She doesn't want to do that to us - and we of course want to be there for her. But reading what you have gone through has prepared me a little.
Old age dementia is different to what my mom has with FTD dementia there may be similarities, but it is significantly worse and much more degenerative, probably the worse of the dementia's out there.
FTD dementia strike as early as in your 40's, it absolutely destroys every aspect of personality, I mean every little bit off it, zero empathy, zero inhibitions, they absolutely lose their filter, they have the attention span of puppy, sundowning is likely the worse symptom.
Old age dementia and other forms are entirely tame compared to FTD dementia.
People assume it is a gradual decline, compared to others, far from it you can often see the degenerative nature in real time. The worse part is, it doesn't necessarily attack memory at first and most of the long term memory stays intact short term memory does suffer a fair bit.
Best way to describe it is
Jekyll and Hyde.
I got lucky getting a place 36km away, also have a DNR in place as well as a advance medical directive, it sounds harsh but the reality is the person you knew is long gone and you only keeping the person alive as it is the only legal method and is cruel and usual punishment.
ADVISE !!! To do this NOW
Have her sign a DNR and advance medical directive, and finally you would have to go to a lawyer costs between 600 and 1.5k to become her legal administrator/power of attorney once her faculties are gone you have to approach the high court for that unless you have thousands it ain't going to be cheap.
Get added to her medical aid, bank, or any other service provider as an admin now. Dealing with these things in an emergency is the last thing you want.
The DNR and advance medical directive is a prickly subject for some, but it is protection for her and your self. You will be surprised how quickly final stages can and will drain bank accounts for the person to die anyways. The advance medical directive puts a stop to any and all family fighting about her care. In other words the medical directive is a piece of paper that tells the doctor to pull the plug and not something you have to phsyically deal with and removes that choice from you. The more distance the better.