i think at this point she may need a nursing home. I work in one and they arent as bad as people think..just make sure you get a good one...that has a good rep....plus most nursing homes have different units..one unit would be for alzheimers while ones for rehab and another for long term care depending on what state she is in....she is getting up there in age....and id be wary of leaving her alone....if her doctor did say she has alzheimers then she could be dangerous to herself or others....not to say anything against her but it is her disease,,,,and old age is dangerous in itself for frequent accidents...falls and such and being 91 its very hard to come back from that. By the way, my heart goes out to you..my step grandfather has alzheimers and it is very difficult to watch the ones you love in such a difficult situation....my heart goes out to you