Trying to make it stop.

My story is about my mother, my sister and myself. When I was a little boy, my parents had some disagreements sometimes. But when I grew up, I knew it wasn't just a disagreement about something stupid. My dad's family had some problems with alcohol. One day, when my dad came home after his work, he was drunk. He began yelling at my mom. He called her a bitch, a whore,... He didn't stop. So she turned around and asked to stop. He grabbed her arm and threw her in the seat. He hit her. My sister, brother and me were watching it. We couldn't make him stop. After some minutes, I don't know how long it took, it seemed like hours to me, my mom said to us to get in the car. She took the keys. And we left. We went to my grandparents. They made us go back. When we arrived, he wanted to leave. But again, my grandparents made him stay with us. I wish he didn't. I still want him to leave. That was the first time I remember him hitting my mother. When I talked with my sister, she said she knew it happened before. It didn't stop. Every time I hear them yelling, I remember every moment he did that to her. I want it to stop. I wish it never happened. My sister can't handle it. She's scared to death. We're falling apart. I don't think I can handle it anymore. I'm tired. I can't put up the brave face I had for 7 years. There's so much going on right now. I just want to make a difference. But I can't. I wish I had a family. I wish I had someone to talk to about this. But I can't. I keep falling down. It's weird. If I'm feeling terrible about this, how would my mom feel? I can't imagine... How long will it take before we all break down?