Is this normal for a 13 year old kid?

ok there a kid in my gym cl i think is on steroids. every time i see im shirtless( every other weekday) he gets bigger, not like a small bigger like a big difference. hee has a 6 pack and huge arms, but at first he had a barely noticeable 6 pack, now he has a 6 pack that looks like the edited pictures you see on protein pill containers, and he just got huge arms, IN 6 DAYS! is that possible? he looks like a 25 midget body builder just starting out....i really think hes on steroids