We've noticed that she's just started to neglect herself. I suspect that she needs help bathing but I fear even bringing it up with her. It's work just to get her to change her clothes so I can wash them. She doesn't like being told what to do and becomes very angry if she thinks we're trying to take away her independence. She lives in a mother in law apartment attached to our house so she is safe and can be monitored.
Yes, it is a dignity issue. We emphasize that caregiving is a favor returned to our parents for the care we received as children. It is consistent with our family tradition and Christian faith to keep our loved ones in family care as long as possible.
With dementia, your loved one will go through stages of resistance and periods of peace and cooperation (hopefully). Your relationship with your parent will evolve over that change too.
Try to keep perspective. Alzheimer's is fatal. Slowly fatal. It is ok to bribe your parent to cooperate...chocolate pudding CAN be on breakfast menu! Throw some of those "living ideas" out and adopt a "bucket list" perspective. The simplest joys could be a vehicle for improved mood and a sense of really living while dying. Do not underestimate your ability to help shape the response, by working the positives and likes your parent has as a person. You might actually get to know him or her in a new way.
Not bathing was a big issue with my cousin who has dementia. It started even before we knew that dementia was at work with her, but soon it became clear. I'd watch your mom very closely to see what else she may not be doing. Often they don't eat, don't toilet well, eat spoiled food, etc. I'd be careful of her letting in strangers and giving out financial information. It sounds like you are keeping a good eye on her with her living next door, but still......I'm not sure there is anything that you an say to her that may cause her to bathe more. With dementia, the reasoning and memory are just not there any longer. I can't imagine that she would pick back up with bathing regularly, unless she's guided through it.
What I found that worked was to just insist as we went about it. I'd run the water and get a wash clothe and starting talking about how she was going to get nice and clean. I acted as if it was my job to help her bath. She ALWAYS said she had already bathed, but I said, I know, but this is special soap that I have and we have to use it. So, he we go and I'd then talk about our plans, meals, tv show, etc. Pleading, begging or threats don't prove helpful, IMO. A bath aid might be a good idea. Sometimes dementia patients respond to them.