Mother diagnosed w/ bipolar l & paranoia 35 yrs ago. Lives alone (my father's home). Future assistance a must! What can be done?

When she was younger, she did most all the things those without medication or diagnosis would do; mischievous, stole things, killed the neighbors dog, burned down 2, possibly 3 houses, that I'm aware of, had an affair, etc. She suffers from severe paranoia and bipolar, has no friends. Meaner than a snake. If she has to wait on anything, she will yell out in public about it and tell them "I'm never coming back to this damned place again!" even doctors offices. She meets people that she doesn't know at the door with a double barrel shotgun in hand.
Her symptoms surfaced very badly right after I was born. My father took her son and me to live with separate grandparents. She wound up in the state mental institution for about 3 months in 1961. Placed on such med's as phenobarbital, it made no difference in her personality except to exacerbate the situation. She got her son back; I remained with fathers parents until I was 4 1/2 and only came home then because my grandfather died at age 54 and my grandmother had to go to work.
She lived with me so many times, I can't begin to count them all. When I was 21 she went off the deep end in a multitude of ways! I finally got her to see a doctor and he told her she could admit herself to the state mental institution or he would have a judge sign the orders! She was there 2 weeks, but no diagnosis.
She tired living alone and with her son, but has never been responsible with money, so she always had to move on to somewhere else; mostly back to me.
After convincing her to see a psychiatrist again (she was very depressed), he asked her to check herself into the local mental institution, after 3 months there and trying multiple medications, she was diagnosed Bipolar w/ a possible borderline personality disorder and severe paranoia.
She now lives in my fathers home (ex husband) after her husband died, her mobile home burned to the ground 2 months later, she couldn't stand living with me or her son and my father (a retired truck driver now) told her she could always stay and take care of his place.
I am now the full time caregiver for a father I barely know (he was gone for over 46 years) and is dying a slow death of multiple medical problems.
After a recent visit to see her, and father to visit his home, there were multiple mental explosions! She never wants to see or talk to me and my husband again or my father.
I have no idea what to do with her. She cannot handle the old house and 7 acres alone much longer. Her SS is gone before you know no it. My father pays the electricity, that I had placed in my name, home insurance and cable bill. I got her a cell phone yrs ago. I pay this bill and she sends me money for the home phone bill. She gets almost $1700 a month between SS and a small check from her deceased husbands pension. It's gone and she's over drawn every month!
She needs to be placed somewhere else as she doesn't take her medication properly and her condition is continually worsening. She would never sign a full POA and I really don't know what can be done. She lives way out in the country and drives her other family members nuts by calling them all day, time after time!
Is there anything that can be done. I worked with advocacy for many years before I retired to take care of family members, but I have never dealt with a situation like this.
She is armed and dangerous! The things that she has done would make a Stephen King novel look mild! Her passed these wonderful genes along to her son, of whom has done worse things than she has. I had to divorce him from my life!
I fear that she will burn down my father's home, without hesitation if told to leave.
I just don't know where to turn to. Is there a professional person that can help me, help her?