An easy thing that can help a lot is putting a clean towel on his pillow. It helps with over night breakouts. Do not sleep on the same side 2 times in a row as that defeats the purpose, sleep on one side, flip, sleep, wash. Two things contribute to acne, DNA and diet. Some people are just prone to breakouts, medication is really the only cure for that. Diet however can be tweaked, many things can set off breakouts fatty foods, greasy foods, sugar, I've even seen dairy cause some teenagers to break out. Elimination diet will be your best bet here. Also if your son has oily skin blotting paper might be a good thing to keep on him so he can use it on the go.
Moisturizing is something a lot of people forget about, they wash and wash and wash and wonder why the acne keeps showing up. The more you wash and use harsh products like acid the more you dry your skin out, this causes the body to produce more oil which in turn traps more dirt in the pores which creates more acne. He should moisturize after he washes his face. I've heard good things about face washes with tea tree oil and moisturizers with olive oil. Witch Hazel also makes a great astringent and is cheap (it's also one of the main ingredients in proactive).