You're not a parent and just a gym friend. You have no right to help him make a decision with so many potential dangers associated with it. If I were his parents and found out you were doing this, i'd definitely have your ass. We also do not allow 'friends' to find this information out, even if they are of age. If neither of you have the time or reading comprehension to find out why giving a 16 year old, test boosters is bad, then no amount of advice will help you. You're just looking for someone to tell you a cycle and that's it and this isn't a place to get it.