Destiny is good, and if his mate has it, that might be the one. Make sure you get the right ‘content’ for it though, there have been a number of extra add-ons put out over the last couple of years, and if you just get the basic version it might be disappointing.
As for FPS age ratings, while you don’t want to see massive blood spatters etc, I think one of the insidious things in some titles is the frequency of dying and respawning (every few seconds in some matches where you’re not doing all that well), which can be frustrating for younger players. And the fact that you might need to spend money after you buy the game if you want the upgraded weapons/characters which are currently slaughtering you.
Battlefront was a bit like that, not as bad as COD though.