^^ Oh please, spare me. The “average” kid - even in private school - does not get 2300+ or take Calculus as a sophomore. The OP’s son had a very good admissions outcome. Maybe it is not one the parent or child wanted but it’s not as if the child is doomed to mediocrity or the parent has failed.
The boy may have been a bit overconfident and maybe immature (?) but this is the learning experience for him. He and the parent has now learned the very harsh lesson of what acceptance rates in the teens and single digits really mean.