Don't shoot a slick trick, the 4 blades and the blade angle is not ideal for light weight. Believe what you will, but COC at 100 grain is what you want. Magnus makes great heads and are lifetime warranty. perfect for a kid starting off. there are many single blade or COC heads available.
Buy him some Black Hornets and he'll be jacked. Those heads are brutal!!
Stingers are great too, they do the same thing, put meat on the ground.
two things it's stay away from, expandable and fixed with big blade angles.
If you can find TruFire T1's, they fly outstanding and are a 3 blade fixed COC but no blade angle. G5 strikers are the same, big steel tip w a even tip to blade transition so basically a COC. Steel force makes nice COC heads too.
Good luck with your search.
Formerly Steve @ G & S