All my mother (99) talks about are inappropriate topics. She is so loud and embarrassing in public. Any advice?

She thinks this 65 yr old guy wants to marry her. She wants to buy a new car and go live with him. He has a partner of 20 years. He's not aware of her delusion.
On top of that she's blew through what money she had, and pretty soon I'm going to have to find a way to support her financially.
She spent 2200 dollars on Publisher's Clearing House. Gives away money to people she doesn't know. Takes her clothes off in front of my son in law. Has a gun she won't give up, called the local police and they came out but wouldn't take it from her. One of these days she's going to kill somone.
She won't flush the toilet and cusses you if u do. Threatens to burn the house down. Won't take her meds as prescribed, won't follow a diet. Eats around the clock is diabetic. Stays up all night every night. Has violent tirades and tantrums. My children can't stand her she's so nasty.
She's incontinent, of bowel and bladder wears a pad but she refuses pants, so consequently the feces runs out onto her clothing, legs and floor.
In the daytime she's fairly clear, but at night she's confused and screams and says she's scared.
I haven't had a decent night's sleep in four years. I have COPD, have had a heart attack. Have high blood pressure. Can barely walk. Need ankle surgery, but can't have it because I have no help with her. I'm 70, I can't work because I can't leave her alone. I am losing my property and home because I can't work.
None of the doctors have ever observed her except a brief time for the office visit. They think she's a sweet little old lady.
When in fact she's a life long manipulator who left her kids for men. Now that her step kids took her money she's lodged here. She's never ever done anything to help me, not once.
I can't get any help from social workers, or the doctors here.
I've called every place I can for help, with no luck.
She needs a structured environment, with someone to watch her around the clock so she eats right, takes her meds right. She just wants to fight and argue with me.

I can't do it anymore. I am exhausted. I can't even leave the house to go to the grocery. Can't take her anywhere because she continuously defecates on herself. All I do is laundry and clean up feces.

I don't want to take care of her. I don't even like her. She's nasty, abusive and has always been selfish. She supported her child molester husband when he abused my daughter. Claims to be religious.
I simply don't want to look at her. I'd rather be dead than stuck with her. She has always treated me poorly but I'm the only kid left and the step kids don't want her.
Before she can go to a nursing home I have to have a doctor say she needs to be there. This little town has mostly nurse practitioners. The hospital and clinic is a joke. They collect Medicaid and Medicare payments and do nothing.
The council on aging offers no helpful info.
I have a durable power of attorney and a medical power of attorney. Still they pay no attention to anything and act like she's fine. She is obviously deaf and confused to anyone who takes the time to talk to her and that is just the tip of the iceberg.
She has become too much for me to care for. I can't keep up with all the behavior, extra cleaning and not ever get any sleep. It appears there is nothing to be done here. I am at the end of the rope as they say. Any ideas?