For Both HP rides, but especially Forbidden Journey, the regular line is amazing and very entertaining (except the greenhouse part for FJ). I don’t think your DH would be bored or impatient. My husband has tolerated them very well! What we have done is step into the regular line and if it is backed up into the greenhouse very far, we step back out and do the single rider line. But you do miss a LOT of the detail in the queue; the single riders lines do skip most of the queue and it sounds like that is the most important part for your son.