If he can only afford one game, tell him to quit wasting money on 60 dollar games and get 3-4 games on sale a few months from now. At least that's what I'd do.
If i'd pick up any new release this month, it'll be Paper Mario: Sticker Star. The very few things on that list actually worth picking up i'd wait until sales for.
I have to admit that I am not a FPS fan (more of an RPG fan). However, I have seen Halo 4 and it's way different than Halo games of the past. It's still an First Person Shooter of course, but it looks different than the old Halo
versions and looks to have more in-depth game play and so I say "Halo 4" by a long shot.