wow... some people are way overreacting. yes it sucks that he got hit, but i've seen rock chips bigger than that. it's called an accident for a reason. I'm sure the guy didn't go out intending on hitting someone on purpose. OP did the right thing in getting the guy's info and at least the other guy is owning up to it, so it'll all end well.
and another thing I don't get is that on a forum filled with car enthusiasts, i'm surprised how many people don't know the difference between break and brake.