re: 7mm-08 advice needed for a young shooter

Full disclosure: I don't own a 7-08 rifle, but I deer hunt w/ a 15" barreled 7-08 handgun (Remington XP-100); it's one of my favorite deer hunting handguns. I only found 2 reduced recoil loads for the 7-08: Remington 140 gr bullet at 2400 fps and Hornady 120 gr SST bullet at 2675 fps. I'd suggest buying one box of each and seeing when one he shoots best. I suspect both will have more recoil than the 223, but he may still be able to shoot it well; you'll know after a few shots. While it's true he won't notice the recoil from a shot taken at live game, I'd still do everything I could to prevent him from developing bad habits at the bench; bad habits at the shooting bench usually result in bad habits in the field. Tips for shooting from the bench:

Use good ear muffs AND soft plugs at the same time.
Keep the number of shots in a shooting session to a minimum.
Consider a shooting sled of some sort to minimize recoil.
Consider a small sandbag (we used to call it a "sissy bag" when I was growing up) between the butt stock and shoulder if it doesn't mess up how the stock fits.
If it looks like he's having problems handling the 7-08 recoil, DO NOT force the issue.

Good luck and keep us up to date!