Best protein Is plant protein. more raw or light steamed or half boiled vegetables.  avoid too much cooking. he should have full plate of fruits in breakfast, coconut water, In lunch /dinner -more and more green vegetables, salad cucumber tomato, carrot, sprouts,  pulses, palak, ghiya,  tori, tinda etc with only 1 or  no roti. This will also bring blood sugar levels down and will improve protein  levels.  stop having milk or milk products of any kind, refined or packaged foods.