My mother lives alone and is mean and nasty to me. She just turned 95. I need help!

APS will say the same thing the lawyer said. "If they want to live this way". My thing would be the bathing. I won't leave the house without a shower. I would find out why she won't bathe. Is she afraid she will fall? Does she have a shower chair. Hand held shower head. Bars to be able to help her.

You say she lives by herself and DOES have her mind. Many hoarders do. You might want to call Adult Protective Services to assess her for safety, as these are often fire traps. Let them handle it and stay out of the middle of it. If they think you will take over they will let you, and if we know anything about Hoarders we know that you will not be able to accomplish anything.
In fact, when APS visits I would not be there. When they call you, IF they call you, you need to tell them you can do nothing and will not be going there, and that they must get her guardianship if they feel she is a danger to herself or to others (fires spread when they happen to nearby homes.
In fact, if you know neighbors, you might tell them you have tried and can do nothing, and THEY should report to APS if they worry re fire.
The truth is that you are helpless in this. I think no amount of "help with her" will change anything. Guardianship would require overcoming that she is mentally intact if not mentally well. Know also that you are not in a position at this time to mentally assess her. She is 95. I would imagine any kind of questioning to assess for Alzheimer's is angrily case aside. She may need EMS to take her to hospital for evaluation. If THIS happens it is honestly the best that CAN happen, as this can be tossed to the Social Workers for some placement and care, and the city may clear the home; often these places are so filled with molds and etc they need to be demolished.
Sorry for what you are going through.

Call Adult Protective Services

Do you have to take her places? If not, I would just leave her alone. Making yourself crazy by trying to get her to do things she doesn't want to do hasn't accomplished the end result. Honestly, with my In-laws, we just had to wait until something happened (a fall, hospitalization) before we could enact any changes.
You could also call your local Council on Aging and see if there is anything you can legally do to help her. Otherwise, I'd just carry on doing what you're doing to support her physically and give up on the icky things that you know aren't healthy (hoarding, unclean body).