/ic/ - Artwork/Critique

I saw my brother molest my little brother when I was 11. I was so terrified, I didn't really know what was happening because I was a sheltered kid. The second I entered the room, my brother left and my little brother was confused. I asked him questions about it and told him to tell me if that ever happened again. I'm scared of leaving for college because I know my brother still does slight things that seem inoffensive from the outside, but they really aren't. If I leave for college, he might do them again. I can't tell anyone, or they'll kill him. He may be a degenerate, but he's still my brother. What the fuck do I do?