Yeah Halo is an Xbox exclusive so That cancels that out.

Call of Duty: Black Ops 2 is a good game I enjoyed the story mode and it was definitely a new approach to the game franchise with all the drones and being set in the future. On Ps3 the online is free so if he wanted to play online and had internet access its pretty basic to set up.

Assassins Creed 3 I believe is not as good as the previous ones but it's still a solid game and just like the others it has a long story line that will keep you playing for a long time.

Check out Dishonored its got really good reviews.

Dishonored - Launch Trailer - YouTube