But I will say that he should be eating asap after every workout. And getting 20 to 30 grams of protein in those meals from a lean source. Along with 40 to 60 grams of carbohydrates. Try to keep the simple sugars in that meal low. Timing meals to be at the end of workouts (swim, weights, etc.) should be the goal. Throw out the traditional breakfast lunch and dinner times. Small meals 30 minutes before workouts as necessary in order to have the energy to complete the workout in a strong manner. And don’t short change the vegetables and fruits, potentially good for those preworkout meals.
It is also important that he gets plenty of sleep. Which is tough for a high school student.