As far as bigger, faster, stronger goes, there are parts of it that could be benefit to the kid. If the coach thinks that the lifting is going to hinder the kids progress he is mistaken. This kid is at a great age to be lifting, and it will only help his future development to a college scholarship. In college he will have to do all these lifts. I have been coaching professional athletes for over 10 years, as well as kids as young as 12.
Strength now equals success later.
I'm guessing that you are training a young lineman. With all the pushing they do on the line, and from the twisting, the initial charge, and so on, the mid and low back is extremely stressed. If he develops everywhere but there he'll have a weak link in his back. This is the off season, so I assume you are concentrating on mass but will add things like pause squats and similar weighted or not weighted plyometrics later. Let me just say as a high school and a former college football player, that while I do not agree that deadlifts should be a primary exercise in high school football weight training, they should be in no way taken totally out of the program.