Yo it might not be just him playing on that account. This kid on mw3 hazza-skh or something like that has 4 people playen on his account non stop, he has 100 days played and ranked 2 in the world for kills
You ever thought that he isn't the only one playing on that account? Or when modded lobbies didn't get you banned that he got into one of those and hacked his stats? Or maybe he's just one of those people like World of Warcraft guy from south park, has no-life?