Friend cutting wrists help!?

A friend is cutting his wrists, and has only told me and another friend who I doubt is going to do anything about it. He refuses to let anyone know about it, as much as I've tried to persuade him otherwise, and expects me to lie to any teachers or figureheads if they get suspicious. I'd probably go along with this if it was some kind of petty problem but I can tell he's on the brink. Really depressed. I'm concerned that if he gets loads of attention from the school he will really get upset, and that may force him to do it again. On the other hand, I really think he needs help, help which I'm failing to provide. I'm telling the school psychiatrist, i'm pretty sure. But I still have my doubts about how to do so. Any help?