First of all, I'd take a look at what he is currently eating and begin to make modifications. Replacing one to two meals a day with a NutriBlast that is perfectly balanced with protein, carbs, and healthy fats is a good place to start. You can get ideas from our new weight loss plan, LEAN. https://www.nutriliving.com/shop/nutribullet-lean
Because he is still growing I would talk with a dietitian about how to modify this program to fit his particular needs. We usually don't encourage children to follow weight loss programs so it's best to seek personal guidance from his doctor or dietitian. You can also search our recipes for lower calorie Blast recipes he can use as snacks to replace other unhealthy foods he may be eating.
And of course remember to stay active!