It's not a delusion (he would not recognize it as problematic) and is unlikely to be a hallucination, IMO.
It's actually pretty difficult to get a seizure disorder dx--so that part wouldn't concern me, in terms of the neurologist.
It does sound like it's related to EF--in that he has trouble switching gears, once it's begun. Still, wouldn't worry about needing to medicate unless it is interfering with his functioning.
Ahh now this is why I posted here... I knew someone would say something and it'd be a lightbulb. THIS: "It does sound like it's related to EF--in that he has trouble switching gears, once it's begun" that speaks to me ... it fits... I think you are on to something with that... It is also says to me he will with maturity and determination find a way to control it better... or maybe he will try adhd meds to some degree eventually...