It hasn't been mentioned but you can be in the entire queue line with your son and once the seater person asks how many, you reply, "one to ride, one to exit" and you will be shown the way out. I would advise that you and your son agree on a meeting place after the ride as some of the places might have an exit away from you are led. If the attraction exits into a gift shop, I would meet him just inside the shop or just outside the shop (you can enter from the exit of the shop at most places). If he wants to do Twilight Zone, no problem there and you will be led to right before the photo viewing area and you will have a lot of fun watching the others exit right off the elevators.
I too had a health problem for five years and couldn't do the thrills so I sent my husband on those attractions on his own. We didn't have a problem meeting up after since we had a preset meeting place we both knew. Very easy.