If he's a motherfucking boss, he could also try a Paradox Grand strategy title, like Crusader Kings 2 or Europa Universalis 4. Might wanna bind pause to a thumb button, but otherwise I hardly use my keyboard at all.
And as has already been mentioned, I would also recommend Divinity: Original Sin. I'm currently co-oping it with my brother, and it's the bee's knees, no doubt about it. Best RPG I've played in a while, to be honest. And it's turn-based during combat, so no reflexes or quick inputs involved.