Like Amelia said, the holistic doctor I'm taking DS to on April 5 (for his food sensitivities and some other issues) also works with a LOT of kids with autism issues, ADHD, etc. And she strongly believes that food sensitivities and sometimes metabolic imbalances, etc play a huge part in it and treatment of can make an enormous difference.
Huge hugs and good luck wishes to you. Will anxiously be awaiting an update!