This kid only eats junk food. Will eat bananas and apple sauce and that's about it.

It may help to get him to help you in the kitchen, some love cooking, some not so much.

But a grilled cheese sandwich tastes better when you helped make it! If he enjoys that, try making homemade bread for those sandwiches, or different cheeses. Make it science experiments!

Think most children prefer a hands-on approach to learning.

If he's used to junk food, you can find many imitation junk food recipes on pinterest using real ingredients. To just get him off of the junk food wagon should take care of or at the least help with the ADHD. Try to get his parents on the healthy food if possible, not going to help much if he eats healthy at your house and back to total junk at home.

When you have time you could talk with him about recipes that use apples or bananas. Introduce him to things he has never tried but sound good to him. Let him pick a recipe that the two of you could make together. He may develop a new found love of learning to create meals or desserts for your household. Make it an learning experience from making a list of needed items, budgeting, shopping, following a recipe, preparing the ingredients, and finally enjoying something new to eat.