Dianecos,
My older brother brought me the video on the ketogenic diet, originating at Johns Hopkins in Maryland. I'm not sure he believed me when I told him I had already checked with our neurologist who told me Beth would not be a good candidate for the diet as she was a picky eater.
When you go on the diet your child has to go off all meds and is given a very high fat diet. Everything is measured and very strict. If your son knows the importance of staying within the regimine he might be a candidate.
An alternative to this might be one of the diets that are used to change the nutrition of your son (something I am looking into for our daughter) that are listed on autism.com...our daughter has brain-damage and seizures and sometimes seems remote like an autistic child, though she has never been diagnosed as such...
Wish you luck in finding something that works and keep with the message board with any more questions, comments or positive results.
Marilyn