Sandy,
I have two girls who, unlike their father, eat like little birds. They barely make a dent in a grilled cheese sandwich. Even with such little appetites, I think that the
Dining plans are great! Here are some suggestions;
You are probably not going to want to go with the Deluxe Dining plan. I certainly can't find a way to make it pay off with my family, though I have recommended it to others, especially all-adult groups and families with older teens.
You should strongly consider the Quick Service Dining plan. Don't assume that going with a "fast-food restaurant" plan means you're getting him only unhealthy foods. Many of the counter service restaurants have some great healthy and delicious options. Personal favorites include the Flame Tree BBQ (Animal Kingdom), Tangerine Cafe (Epcot), and Sunset Ranch (Hollywood Studios).
Also think about the standard plan, as that has you at just one table service meal per day. And you may be doubling up some of those "credits" for some more entertaining meals.
I am glad to answer any follow-up questions you may have. Just visit me at my bio page to ask!
Have a magical (and delicious) vacation!