RE: Too young for a " real" bow?
I think he's old enough. I grew up with a long bow and a recurve. Just target practicing with my dad and shooting around. Then when I was eleven I got my first compound bow. Started hunting at 12, which is the first year allowed.
I think anything over 40 lbs. will kill a deer with the right shot placement and good broadheads. I shot my first deer just after my 16th birthday pulling about 47 lbs and had a clean pass-through, even breaking two ribs!