If I were you, I'd get him the Ruger American in .243. Good all around caliber for about anything and a lot less recoil than the 7mm-08 which equates to being a lot more comfortable to shoot well at that age. You can even find a package deal including a Redfield Revolution 3-9x40 scope for right around $500. These are really really good rifles with many features found on rifles easily 3-4x as expensive.
If you wanna run with the big dogs, you gotta get off the porch!