btw, not sure if my term "appropriate daydreaming" is sellable as it is somewhat of a repackaging of "bored," maybe "lateral exploration" or "self-driven enrichment." And that's the gifted angst bit.
But I think the critical part is getting them to not penalize him for impacts from his disability and changing their lens to see those for what they are. I believe they need a baseline of what demands are EDS related, before they asses attention in general.
Motor planning can be much more intensive than just getting from here to there, potentially down to just below conscious control like position of the hand, adjusting to any current pain, remembering the path that a letter takes where to place each element, reviewing those plans with current muscle fatigue levels, current joint issues, current pain, revising, continuing, checking feedback, etc.
It would be an interesting sensitiviy training to have people operate a four axis robot arm to try and write their names while answering math word problems. Even an Etch-a-Sketch might illustrate some of the concept or writing with their foot.