I have had first-hand experience with food poisoning (not on a cruise), and it usually takes several hours (8-10?) for the symptoms to show up. I know exactly what your son went through, and it's not something I would wish on anyone. However, is it possible that he ate something prior to boarding the ship that made him sick? If only one person gets sick after eating at a dining establishment, it's difficult to pinpoint the source of the food poising, especially if several people had the same thing to eat at the same place and on the same date. In my case, it was a seafood restaurant, and my wife and I both had the same thing (grilled shrimp). It's a place we've been to for several years and never had a problem. All it takes is one piece of contaminated food. I'm guessing but can't prove it was a contaminated shrimp. Will I eat there again? Yes. Will I order shrimp again? Hmmm. Haven't decided for sure on that. There isn't any medicine that I know of that will instantly counteract the effects of food poisoning. It pretty much has to run its' course. I'm sure the ship's doctor knew this, and knew there was only so much he could to make your son comfortable. Your aunt and uncle were certainly faced with a dilemma. Stay on the ship and try to make the best of their cruise, or get off at the next port, cut the cruise short, and go home? Perhaps that is more likely what was discussed between your aunt and uncle and the ship's staff. Since, as far as you know, your son was the only one on the ship to have food poisoning, it would be extremely difficult to pinpoint the exact source of the contaminated food, and whether it was something he ate on the ship, or prior to boarding. Writing a letter to RCCL probably won't do much good. You'll probably have to chalk it up to one of life's unpleasant experiences. I'd say your aunt, uncle and son deserve a do-over. Go on another cruise (maybe a different ship), and if possible, maybe you could go too.