Of course you can, why wouldnt you be able to?
Because steam doesn't seem to have the game available in his country. So since he is having issues purchasing it off of steam (it's not showing up or something), he fears that he wouldn't be able to activate it with steam either, even if he had a physical copy.
This is all based off of him having the PC version though. If he got one of the other versions, it wouldn't be an issue, but I'm assuming he wants the PC version here.
TC, the one thing I can add to this discussion is if you went to an area in which steam wasn't blocked/ wasn't missing skyrim or whatever your exact problem is, you could most certainly at least activate it in that region. And once it's been activated, you could just select the play offline option on steam and you'd never have to worry about needing to connect to steam for skyrim again.