ok, I may get heat for this... but if the guy is otherwise always / usually eating clean, then one cheat snack or meal isn't going to destroy him... unless he's dieting down for a competition or something.... in fact, I think alot of people have one or two cheat meals per week, on weekends, while otherwise eating clean.
I'm not saying make a habit of it, but if you did it once, don't sweat it - it won't ruin you