I'm taking care of dad, mom's been abusive to me and wants my dad to go back home with her. Any advice?

Sounds like your mother and father are both quite ill. First, you need to make sure you are emotionally, mentally, physically and spiritually healthy. Otherwise you will just react to them and what an ugly thing that will be.
Once you know you are doing ok. you could ask your doctor for help. Professionals use what they call "theraputic lies" or fiblets to get patients to do what they need to do. Like how to get your mother to receive the help she seems to desperately need. I can't quite understand why she was not admitted to the psych unit after her violent outbreak. Did you file assualt charges? Same for your Dad. Do you have a geriatic center in hospital near you. A full physical and mental evaluation, might help you know what exactly you are dealing with.
Let us know how you are doing. Wishing you a good outcome.

Oh and by the way, once I actually filed for guardianship; it was her court appointed lawyer that actually found out/interviewed her doctors and got med reports and her diagnosis as Schizophrenia w/Parnoid Features/Demensia....If it wasn't for them doing their court appointed lawyer/temp guardian duties, I'm not sure if we would have actually won the case w/out medical evidence. So in my case I had how she was living evidence, bank statments, bills, witnesses etc...but they were the ones that actually got the medical proof we needed from her doctor reports/interviews and statements.

How old are your parents? If both has something cognitive, mental etc...going on do you have a Medical, Durable, or Power of attorney? For me I had a Durable POA (not effective unless she was deemed incompetent, then she got smart and revoked it..lol), but I didn't have a medical POA, so her docs wouldn't tell me what was really going on, except basics when I went with her to doc appts. I would complain to her docs, social worker etc.. how she was, and the things she was doing..but they would say she's fine. It was hard to finally get up the nerve but I finally filed for incompetence/guardianship of my mother, and it was something that had/needed to be done...or in my case, eventually my mom would have been a 86yr old, in jail (scammers even had her open bank acct so they can money laundry, and she gave them her money too; she wouldn't pay any house hold bills, started getting violent, moody etc.... The judge ruled that my brother and I would be her guardian, and to this day she's still pissed, but we did what had to be done...You have to do what you have to do, that way you can at least say you tried; and that's the way I looked at it when I went to court against my mom. It was the hardest things I have ever had to do..me on one side of the court room and her on the other side...

As far as mom goes I am not sure if she has cognative problems as I said I was taking her to be evaluated. She will not allow this at all. Dad does have damentia and I am trying to protect him. I would not doubt that mom does but I just cannot find out.

Thank you

You did not mention here if either your mom or dad have any cognitive issues, such as AD/dementia. If that is the case, people do get aggressive and sometimes, physically violent. If you suspect that is the case, you need to get a proper diagnosis and get her on meds. There are medications out there that will calm her aggressive behavior. Let us know more details so we can properly give you guidance.

Thank you for your response. I have been told these things by others and I guess I just needed an unbiased opinon

Stay away from your Mother; she is toxic and abusive. File a restraining order.