I think it's his personal choice to not have any social life, so I don't think there is anything you should/can do about it.
From reading what you typed, I don't think he's that bad of a roommate.
Sure, you sometimes want your roommate to say hi, but as long as he's not disturbing your social life and/or academic life, I don't think there is any problem there.
http://www.baseball-reference.com/players/l/latosma01.shtml. Mat Latos - Sponsored by the Fantasy Baseball Cafe!