Valery you are an angel for being there for your Mom. She is just naturally getting older and she just needs some TLC. I can understand your husbands behavior but family sticks together. I am in the Nursing field and I can suggest you ask around your area for some in home care. Medicare will pay the bill and you will need to get her to a doctor. I wish you all the luck in the world. Some people would have just walked away from the situation.
If need be call Social Services and have them come out for an evaluation. This could be a great start for you or the worst nightmare depending on how they go about it. You definitely need help and so does she.
I wish you all the best.