Just curious- is this an NHS-visa thing?

I'm really surprised that a doctor would say this to someone.  When you're 20, it doesn't really occur to you to challenge something a doctor or any person in a similar position advises you.  Your friend probably won't bother taking this a step further, but if I were him, I'd ask the doctor to put his advice in writing.  Just in case, when he gets back to his home country and another doctor says there's an issue that is now worse because it wasn't dealt with earlier, that letter will now become "exhibit A" in a malpractice suit. 
All your friend has to say is that the airline is wanting a letter as proof that he is fit to fly.

As far as flying, he's probably ok there.  I know with BA, you can fly 10 days after any surgery that doesn't involve the heart.  Every case is different of course, but that's the general guideline. 

Well after talking with him today, he's still leaving tomorrow.  But now I think its a combination of things-  1.) He's still in really rough shape, dizzy, balance issues, etc 2.) The doctor basically said he's not allowed to work for a while or do anything like sports or any other kind of activities or whatever, so they may have thought he'd be better off at home with people to look after him 3.) He may have said, okay, I'm 20, I'm all alone here, everyone I know and trust is at home, I'm not doing well, I miss things from home- my WP expires in 3 weeks anyways, mine as well just go home, especially since he would have to be home all day alone anyways and sitting in front of the tv anyways and not do anything 

So I wished him the best of luck. 

I think I'd do the same in his situation.  Poor kid.

Vicky

I think I'd do the same in his situation.  Poor kid.

Vicky

Definitely!