Abused child at the school where I teach. Resources seem exhausted. How do I help this kid?

The thread from the bullied kid inspired me to turn here for advice.

The lead in: As a music teacher, I have to have an expectation regarding concert performances for my students. A question from one kid who said his family didn't have a car led to this...

We talked about possible solutions, which included carpooling with a friend, etc., but in the end I simply asked him to have his parents contact me and we'd figure out a solution. This eventually led to me being called to talk to the principal - and I don't know how they even got involved with this, but I'm both glad and sorry that they did. I was told in no uncertain terms that the kid's parents are all but unreachable, and that he gets abused - brutally, apparently - on a daily basis. They told me the kid is terrified of his parents and that involving them would be a bad idea. The implication was that I should leave it alone and not penalize the kid if he can't get to the concert, but I forgot all about the concert as soon as I heard, "He gets the shit beat out of him every day."

So I asked the obvious question: Why isn't social services all over this? I got the answer that they have been contacted on nuerous occasions and they have a nice thick file on this family. However, it doesn't seem to be helping if the kid's still in this situation. This is a part of the country where an agency like this is spread thin as it is.

I'm glad I had this conversation during a planning period; I needed some time by myself to regain my composure. As a parent of two kids myself, I can't even comprehend a child being terrified of his own parents, and I'm swimming right now with a combination of rage and fear. I mean, what is this kid going through right now as I'm sitting here in my perfect little life? This isn't even about the damn concert anymore.

There's got to be other avenues to help this kid, but I have no idea what they are. No reasonable suggestion ignored.

tl;dr The kid is terrified of his parents. Social services appears impotent. What other recourse to get this kid the help he needs?