J.S.
great responses and I tried most of them. we added 3 chocolate ships to a cup of warm milk, just enough flavor but not too sweet, or a 1/4 serving of powdered choc milk, it was beige milk instead of white. And mine needs her milk warm, even now at 3yrs she prefers it that way. she will drink it from a tiny glass cold at dinner occasionally, but really likes it now warm in the morning or if she haves it at night. She likes all of her food warm, very frusterating when she doesn't come to the table or start eating right away.
Good luck! He will be fine, you just need to start leaving him for someone else to care for and things will work themselves out.