I've been told that about recoil (and deafening muzzle blast, too) since I was a kid and for me at least, it matters a whole lot if you know the rifle is going to hurt you and make your ears bleed for three days. I think that whole attitude is a disservice to a budding young sportsman, and if he isn't comfortable and confident with his rig before going after game, ha may not make a good shot and he may lose interest permanently.
Fiver said it best......check in with the KID and keep a barometer on his feelings as he tries different things. If an adequate load in the 7mm is uncomfortable for him, try the Max, etc. I bet he gets used to slightly heavier rifle recoil pretty quickly, but as they say "once bitten, twice shy".