It feels awesome when you know when to stop
You played Mass Effect 1 and 2.
If he did, then he might as well play part 3 too. I'm actually playing ME3 right now, and I'm on the final mission as I'm typing this (took a break to check the Codex). I have to say that this one has been the most enjoyable of the lot, and recruting as much help against the Reapers and collecting as much War Asset points as possible has been fairly engaging.
With that said, the game itself is still a popamole cover shooter, so that fact alone makes it impossible to recommend this to people who're incapable of enjoying games that lack a deep and tactical combat experience. But if you've managed to get through the first, or the second game (or both), and did that without getting a massive headache, then there's really no reason not to play ME3.