Welcome to PC!
I'm so sorry you're going through all this right now. I can so empathize.
I had issues with my family-- alcoholic mother, father in denial, terrible arguing and drama from the time I was a teenager. I was always the peacekeeper and listener for everyone, even back then, but it wasn't til I got out of the house when going to college, and realized like you are now, how messed up things were. It was then that I really pushed therapy on my family, truly believing I was helping and that I could save them. It took several tries, the situation getting worse, and issues coming to a head in a big way about a year ago for me to realize the painful truth: I can not save them, and they don't want my help. There was a lot of greeving for me that my family may never change, and it was a difficult time. But it gave me strength to take my life into my own hands, as one of my therapists put it, and really put my energy towards taking care of myself. I moved out of the house, what I hope will be permanently, this past June.
I've taken a position that's more neutral now. I'm living my own life. I still care very much about my family but I can't be caught up in their drama. I have enough emotional issues (many of them unfortunately made worse by the environment growing up) not to take on more by trying to fix or figure out their problems. Sometimes I get the sense that things are getting better, other times I think it's just an act to maybe try and get me to move back in with them. But in any case I'm staying right here no matter what they do.
Sorry to go on and on, but your story so resonated with me.
So to summ up: My advice? If you want to try to intervine with your family and seek therapy on their behalf, then go for it. I know for me I had to try this several times before I realized it wouldn't work. People telling me it wouldn't wasn't enough. But what I learned was finally that they have to be willing to take care of their own issues, and I'm not responsible for them. And the best thing is support for myself. So find a therapist if you feel you need it, or go to a support group such as Al-anon or ACOA. Or call the helpline. Try and have things you enjoy in life, and a life outside family drama. Most importantly, take care of you.