You mean on his gamertag page where it says what he's doing? That happens a lot, he was probably playing something WWII and put in MW2. The game changed but it hasn't changed what he's doing yet
One of my friends did the same thing, it said he was playing Gears of War 2 but his action was "Level 19 Infiltrator Difficulty: Veteran". He was playing Mass Effect 2 before he put in Gears.