My Mom's living with dementia, refuses to see a doctor or groom herself , is in need of daily assistance. Any advice?

My brother lives with her but does nothing for her, she refuses to see a doctor, talks to herself and is in need of daily assistance (taking medication, grooming, meals,etc). No one seems able to help or care to (other family members) and I have epilepsy/seizure disorders and do not drive, is their an agency that can step in to assist, I don't know where to turn, and when I ask her last time she went to the Dr. she does not know or lies that she saw a doctor from the past who is now deceased, my brother who does live with her doesn't seem to care about her well being or needs.I have my own disability and health issues so I'm not able to assist at this time, can anyone help?