You will find many PC members with similar family dynamics here, is my guess. I'm one of those people. Family therapy won't necessarily solve the dysfunction in your family system. It does sound like your parents and brother have triangulated you (left you out, as the family scapegoat), to keep the focus off of themselves and on you. Most toxic family systems have the one healthy family member who becomes the scapegoat (victim). The other family members are so traumatized with their own problems, that they refuse to look at themselves or take responsibility for how their problems effect other people. So, they look for the closest victim; the scapegoat of the family who is the most mentally healthy person who isn't afraid to be themselves (this terrifies the other family members, fyi). And, they attack the scapegoat, verbally, emotionally, physically...just to keep the focus off of themselves because they have so much self-loathing.

I'm my family's scapegoat. The way I managed is, after my family tried family therapy for about 6 sessions at my behest, they quit because the family therapist called them each out about their toxic behaviors. So, rather than stay and try to repair our relationships with each other, they each quit. That was all I needed from them, to realize that I have to leave them all behind and recreate a family system with other people who come into my life.

You can suggest family counseling but don't expect them all the agree to it. They will be forced to acknowledge their contribution to the dysfunctional family system and most are unwilling to do that, even with the help of a family therapist.

Otherwise, you can draw strong boundaries with your parents and brother about your interactions with them. For example, don't plan on attending any family gatherings with them ever again. Stay away from them at the holidays. Don't go to the house for their birthdays or any events where they will be. It will be difficult and feel strange at first, but you get used to it. I have been estranged from my family for a long time and I no longer dwell on "what once was."

If you really want to spend time with them, you call the shots. You can tell your parents, that you will only see them at your place without your brother, for example. Cut your brother out of your life completely. He is a danger to your emotional and physical well-being. Just because they are your family does not mean you are required to take in their abuse. Family estrangement. Sibling estrangement. There is a lot of research online about this topic, and you can read about coping strategies. Good luck.