Know anything about Pervasive Development Disorder-Not Otherwise Specified?

PDD-NOS is a diagnosis (rather vague, as you can see) at the milder end of Autism, Asperger’s spectrum and is apparently easier to remediate. I have a tiny male friend (almost 2) who is developmentally slow, and am wondering about diet (no gluten, no casein, etc) cranial-sacral work, and other alternative treatments in addition to OT, BT, ST, etc..provided free by NYS.