I'd find out whether it's a complete fresh build, I.E new rods and pistons so needing to be run in.
Then as said above, talk to him about a low boost setting so he can get used to it.
You never know, he might be a real petrolhead that's had experience with very capable cars! You just don't know these days, my friend drives an E46 M3 at 20, and had a VXR engined boggo Corsa C running well over 300bhp at 19!