I would like to see him eat a lot more protein and a lot less carbs. Good protein, not burgers and sausages, will fill him up leaving less room for the other stuff. I have a son this age, but a lot smaller, so it wouldn't compare. My son eats a lot for his size, but I only feed him meat, veggies, and a little fruit, with very few treats. I think you are fantastic to be thinking/doing so much for this boy :)