S.V.
We have always lived by the standard in our house that you eat what is given to you or you don't eat. There are times where someone chooses not to eat, but if you constantly give them choices about what they eat they will always dictate the menu and you are the authority, not them. If he is hungry enough he will eat. We have 4 healthy boys (6,5,3 and 15 mo) that we hold the expectation to and everyone is alive and well fed. It may be hard at first since he is older, but it is well worth training him in this expectation. I have a feeling you are right about what is happening at his fathers house, he is probably eating well because dad maybe gives him choices about everything. Hope this helps :)