I can’t stand my stepfather

I’m 17f living with my mom and her bf, and have been since I was around 8-9 and I can’t fucking stand him. He has always been borderline abusive to me and my two siblings (15f and 19m). I’ve never liked him in my life, at first it was just because my mom gave him more attention than us, but soon after he would begin with the yelling, threatening, breaking things, etc. He stayed with us a lot in our old house, and money was tight so we moved in with him quickly (she had known him for longer but wasn’t dating him yet). My dad now lives many states over with my 19m brother so it’s not like I can just move in with them either. They are horrible for each other, both alcoholics who have struggled with harder drugs in the past, but we would have nowhere else to go, which is why I believe my mom continues to stay with him because that man has absolutely ZERO good qualities. I think my mom is just scared of him because she has never once stood up to him for us, even when he says we deserve to die, ungrateful, threatens us with belts, breaks doors and walls, and says the most awful things you could imagine to us since we were just little kids. What could a kid 6-9 years old possibly do for you to tell them and others they deserve nothing in life, and even scare us so badly when we were little we had to run outside and hide with knives. My mom has chosen him over us so many times I don’t know if I can continue talking to her when I’m older. My mom isn’t the most loving mother ever, but she can definitely put on a good act. I’m not really asking for advice. I just wanna vent. There’s so much he’s done to us but I think my brain kinda blocks a lot of it out so I don’t remember. Anyways, just a vent.