Reddit reviews The 36-Hour Day, fifth edition: The 36-Hour Day: A Family Guide to Caring for People Who Have Alzheimer Disease, Related Dementias, and Memory Loss (A Johns Hopkins Press Health Book)

Your mum is lucky to have such a supportive family. I think Alzheimer's is harder on the caretakers than the patient, since the patient becomes less and less cognizant of what is happening to them while the caretakers watch the changes become more and more debilitating. I've recommended this book on many threads in this subreddit, but in case you missed it, have a look at The 36-hour Day.

Keep in mind at all times that your mum simply cannot do things she used to do, so avoid saying things like, "Don't you remember...," because she can't. Just repeat things as though it's for the first time, because for her it is. It's heartbreaking and frustrating at first, but you get into the rhythm of it and settle into a new way of communicating with your "new" mum. If people correct her, she will start to withdraw.

You will start to feel like you're treating her like a child, and in some ways you are, but it's just to keep her safe and as healthy as possible. It's difficult to treat her like a child while thinking of her as the person she always was, but you can do it, and I believe that on some level she will appreciate it.

I wish you courage and patience. And please, as peace_core says, vent all you want. The alz.org site has message boards, too.