Having a forum to express it is a start. I come from similar life experiences, sick mother, abusive ex-stepfather. The way I've dealt with it that works for me is, finding out what sets you off. I usually recognize the moments right before I explode, and walk away. Even if it's for only a couple minutes. I go outside (weather permitting) and sit down. Close my eyes, clear my head, and just breathe. Then while at home, I close my door, turn off my phone, and my head and do something mindless. Watch Netflix or play a game. That may not work for you, but my best advice, just breathe.