My brother and I have not been able to get an official diagnosis of dementia on our mother. She refuses to go to dr appt and if we "accidentally" end up at the dr office she throws a fit and refuses to get out of the car. Short of man handling her we have not been able to get her there. She won't take medication. She denies she has any problems. She won't bath, wash her hair, let us get her toe nails trimmed etc. I could continue on bui think you get the main message. The neighbors complain that she will knock on their door to ask a question at all hours or will walk by and yell at them for something that she perceives as being wrong. We don't have POA. To make decisions for her we will have to get to dr.'s to agree that she is incompetent. We can't get her to one let alone 2 dr.'s!
It sounds as though she is in need of guardianship. It may be better for a publuc guardian to be appointed.
If she falls, or becomes ill at home, call 911 and have her taken to the hospital for evaluation. Once she's there, you can explain her unhealthy living situation to the social work department before discharge. Sometimes emergency guardianship can be granted in a situation like that.