Hi Julia. Sorry for my lateness. I’ve only just seen your reply. It sounds as if you’re already pretty ttuned to your son’s needs, but hope learning more about PDA proves useful. Awareness in the US is beginning to spread a bit I think. There’s a US-based support/advocacy group online here, if it’s of interest: http://www.pdamatters.org/what-is-pda/

Best,
Neil.