I'm being totally selfish :(?

I'm leaving for school this fall, and my college is 4 hours away from my hometown. Honestly, I only wanted to go to a school so far away to get away from my dad. When he's angry he gets very confrontational and aggressive. I would be able to leave and not look back except for one thing. My little brother lives with my parents. He's only 8, so I don't know how my dad will react to him if I'm not there to... diffuse his anger I guess. He's been better about controlling his anger for the past few months, but it feels like he's going to erupt at any time. My dad's never hit him except for spanking, but I can't tell how he's going to react if my brother pisses him off. If anyone has any advice about what I can do about my brother, I'd really appreciate it. Thanks.