I feel it's a little early to say he's stuck in it. It's both appropriate and healthy for him to grieve for what is lost -- whether it's a person or a time of one's life. Time will tell if he can get it back together or not.
Re-enrol, get some more friends, but this time do some actual work, like wot Lauren did. and things may not be so bad.
Do it before the ability to study evaporates altogether & a life washing dishes is your only horizon.