Is he hyper mobile? Does he have low tone? There seem to be a disproportionate number of kids on this board with connective tissue disorders, all of whom have 2e type issues (as far as I recall), a diagnosis of which is purely physical and might get him accommodations on those physical grounds? It might be worth lookin up hypermobility syndrome and Ehlers Danlos Syndrome (and maybe marfans) just to see if any of it fits. Might be wayyyyyy off base there.