Another vote for Orlando Regional Sand Lake Hospital as it's fabulous! DD2 had to be hospitalized last year - too many illnesses to list, all caught in WDW. They ambulanced us over to Arnold Palmer's Children Hospital which was even more phenomenal. We orignally went to Centra Care Clinic right outside Downtown Disney - never again! Awful service, hours long wait (service CMs for regular appointments), doc missed her Rotavirus, etc. I would highly recommend Orlando Regional over Centra Care - several friends & family have also been to Celebration, which is owned by same group as Centra Care, but we have never been.
Hope your DS is doing better - hopefully for his sake, and everyone else's you are staying inside just in case he is contagious.
Healing pixie dust to your son, Tiger