My father recently had a stroke, we both have ADHD, his is untreated. Since the stroke, most of his impacts have been cognitive, not muscular and most of his cognitive issues relate to worsening executive functioning across all executive functions, but particularly exacerbating the worst issues attributed to ADHD.

As you would know ADHD is a problem with regulation, not capacity however with this stroke it appears that his capacity has fundamentally changed and is further impacted by the dysregulation.

It's still early, and we haven't seen the specialist yet but I'm taking this hypothesis to them and (if I remember to) will update/edit here with their response.