I understand you are talking about a youngster, but if you happen to buy a brake specific to caliber, get one that directs blast outward at 90 degrees. They are slightly less effective for recoil, but SO much more comfortable for the shooter. Less noise, less concussion. And with a .243 or other similar recoiling cartridge, entirely adequate.
Normal to longer barrel lengths are another way to keep him farther from the blast.
I promise inches matter in that department.
I hurt my hearing and got a lot of mild headaches with a high dollar very effective big name brake, no more of that for Me. Good luck to him.