Zara,
The most important thing is that he takes the chelator. It doesn't matter how you give it. Whatever food he will eat with the tablets crushed and mixed in is fine. Bananas are a very good food and recommended. Potatoes are also very good and most nutritious when not peeled. Wash the skins before using. It is best with the skin because that's where most of the minerals and much of the fiber is. He needs more fiber in his diet so he isn't constipated, and remember that insufficient fluid intake also adds to constipation, and that when using Exjade, one must also take much water regularly to help protect the kidneys and liver. Keep trying new foods, especially fresh fruit and vegetables, and try to use breads containing whole grains.