If you are looking at a .308, I don't believe recoil should be an issue. I shot a 30-06 when I was 6 years old in our backyard in Anchorage AK. I think my dad was seeing if it would knock me over and to the best of my memory, I stayed upright. Nevertheless, if you are concerned about recoil, don't get an ultra-lite rifle. Weight matters with recoil, the more weight, the less the recoil.
That stated, if the 14 yo is going to be shooting it, I would NOT get a muzzlebreak since the damage to his hearing could be significant, especially at such a young age. Get a good recoil pad and a rifle with a bit of weight to it. In .308, it shouldn't be an issue.