It sounds like your son needs to switch his workout. A lot of people get into a routine and do the same lifts over and over. When you hit a plateau, you need to change your workout. For example, if he uses the bench press for his chest he should stop using bench press for two weeks and instead use dumbells. Another thing he could try is to use the smith machine and load it up with about twice what he can normally bench and instead of benchig the weight hold it up until his muscles reach exhaustion. Do this 5-6 times instead of benching for two weeks. Your kid also needs to make sure that he is not over training. If he is lifting every day his muscles will not have enough time to recover. Make sure he lifts each muscle group only once per week in a direct workout its ok to indirectly work our a muscle group more than once i.e., your tri muscles get worked out in doing bench but you should work out your arms directly another day that week however, you don't want to directly work out a muscle group twice a week i.e., you should not work your chest out using bench, incline and decline more than once a week).
Once you have made sure that he is lifting correctly, have him add NO Xplode from BSN. NO Xplode is a prework out supplement that will give him more energy and better muscle pumps. NO Xplode is an energy booster that ups the body's level of NO2 and increaases blood flow to the muscles. Its completely safe and is not a steroid. He may also try using ZMA. You take ZMA before going to bed on days you work out and it helps with muscle recovery.