To summarize everyone here that has been in the military agrees on one thing, if he turns himself in before they find him the punishment will be minimal, if he's picked up J-Walking he's toast.

I think its a MBshop first to have this kind of consensus so for goodness sake, tell the guy to turn himself in.

A quick google revealed a GI rights hotline 800-394-9544. I won't list the website because they are not my cup of tea.