No problem, that's around the age that many start.
If he adds training to running & wrestling, tell him to buy bulk, relatively inexpensive protein powder to use to make protein shakes consumed between, not with, meals. Those levels of activity will require more sustenance to repair and build tissue. If he's not fat, even a weight-gain powder would make sense given that he'll need and will burn off the calories & carbs.
He should start by hitting each muscle 2-3 times a week, going to failure most or all the time. Workouts not more than an hour-intense rather than lengthy, moderate sets in the 6-10 range per muscle covering basic bodybuilding and power moves like box squats, bench, curls, lying extensions, dips, chins, rows, military press. Clean & jerk is excellent for sports applications.