Not sure how old he is but make sure he’s aware of how hardcore Steam is about cheating.
It doesn’t completely destroy your online experience but it will annoy it. Reading through this
there’s a person on there who wasn’t cheating, they just had a mod turned on when they were logged into Steam they’d forgotten about or something.
So yeah, I guess make sure he’s fully aware of this side of Steam: you can’t really game without a Steam account these days, mind.