H., I encourage you to become your own best detective whenever your son is diagnosed with something. Doctors and therapists are wonderful consultants, and they can be very helpful! They are also human and can be wrong. So be your own best detective, consult with any experts you wish (docs, therapists, other mothers who have kids w/ similar diagnoses - like you're trying to do here on mamasource), and THEN make your own decision using your mothering instincts + your information.
I am wondering if your 5 yr old has ever been tried on a gluten-free, milk-free diet for a period of 6-8 weeks to see if any of his symptoms go away? So many children have undiagnosed food allergies these days and it truly affects their whole being (from sleep to attention to immunity). I've met too many moms and their kids who struggled for several years with similar issues as you are describing only to find out that their child had a food allergy or a gluten intolerance (like celiac disease) -- and once these kids were eating foods that were safe for them and didn't irritate their bodies so severely, their behavior changed, they blossomed into kids who were healthier, able to learn more easily, etc.
If you are interested in researching this further, some great resources to start with are:
* Dr. Doris Rapp's "Is This Your Child?" (typically available at your local library for FREE)
* online forums where parents of kids with food allergies and intolerances are in the process of diagnosis and recovery (for example, google "forum food allergy children intolerance celiac" and start reading, or google "GF/CF diet", or google "ADHD and food allergy" or "sensory integration" and "food intolerance")
* read about the many, many subtle symptoms of food allergies and celiac disease (gluten intolerance) in children and how these are frequently missed by doctors, yet the conditions are very responsive to diet changes
* keep a food journal where you record what your children eat and how they behave, and start to look for any patterns
* check out Dr. Sears page on "Tracking Down Food Allergies"
http://www.askdrsears.com/html/4/t041800.asp
Best of luck to you! As the mom of 2 kids with food allergies, I've seen first hand how their behavior can be HUGELY affected by food and how exhausting it is to parent my kids when they're having a reaction after eating something they're allergic to (and how much EASIER and more fun it is to parent my kids when they're eating a diet free of their allergic foods!).
I encourage you to consider diet as a possibile culprit of the issues your own kids are going through. Discovering a food allergy and removing that food from their diet would have a very positive impact for your children (and therefore your whole family). Just one thing to think about - it may not apply to your family, but you'll only know if you research it and do what you need to do to rule it out. Hope this helps!