Find a way to share a simple statement that it exists, so he will have the information when he is ready. Understand, though, that he won't be able to change things until he is ready/desperate enough. At least he will know that there are people out there who understand how he feels about food. He already knows he needs to lose, but weight loss diets tend to make things worse, hence the yo-yo. They are demoralizing and he is already overeating to not feel that way. Accept him as he is and pray for him to be ready. He needs love and acceptance more than anything else right now. (that doesn't mean accepting the food behavior but him as a suffering human being.). Thank you for caring about him.