When buying a bow for a 14 year old you should get a bow that the draw length can be adjusted as he grows so you dont have to buy a bow or new cams or modules every time he has a growth spurt.
there are many bows on the market that fit this bill
I would recommending you considering one of the HCA bows that are avalable with the per-fex cam which has50# to 70# of draw weight adjust and is adjustable from 26" to 32"