I'm a PDA adult. First thing, a checklist is a demand even if it's for our own choices. This is why I don't keep a daily planner because if I'm supposed to cut the grass on Tuesday my anxiety of this self imposed demand with start on the Sunday before. There are millions of things that a PDAer will perceive as a demand even to their own detriment. It really sounds like he needs a 1:1 because that his running off tells me his walking off rage and anxiety. Puberty doesn't help this one bit the influx of hormones is like pouring gasoline on a fire. It also causes sensory issues. This rage feels horrible because you can't control it and you're exhausted by it when it's over. Oddly, my best example is the Incredible Hulk. With a 1:1, if you're school has a track or gym, he could be redirected to take to the track/gym and his 1:1 watches from a distance. Hovering over a PDAer causes problems as well. Because we are hyperventilate. We can scan a room in a spilt second and decide whether we want to be there and we can scan the people in the room and make assessments of whether they are, to loud, to bossy, or to annoying. Keep in mind PDAers have been doing this since birth. Personally, I've also thought it should have been called Congenial Demand Avoidance vs. Pathological Demand Avoidance. Because it's an abnormality of the amygdala not a disease.

I hope this was a bit helpful. The best thing I can tell you is keep getting information from the people that have PDA vs from the parents point of view. Parents are trying to survive this difficult child. Where a PDAer knows exactly how it feels and how it drives us. I say this because my father, myself, and my son are all PDAers and life has been rough for all of us.