you are right to be concerned, any high tension haircut WILL cause traction alopecia. Check out venus williams, or the model Naomi Campbell. Deeply recessed hairlines because of stupid hair cuts. I have seen it a lot on wommen too with NW2's who would become instantly insecure if I told them about the damage they are doing to their hairlines. The good news is ur son is still a NW0 and if there is any traction alopecia it is extremely small and in areas he is likely to lose anyway as his hairline matures into a NW1.