How do you do the seemingly neverending illness quest on HorseIsle

Go to Shellton on Turtle Isle. Go to Atreyu's Cabin. Ask him about his luckdragon. He'll ask you to go find medicine. Go back to Horse Isle and ask the vet in Appleton if he has medicine. He'll tell you to go to the vet in Tropicton. Go to Tropicton and ask the vet there if she has medicine. She'll give you some. Go back to Atreyu's Cabin and give him the medicine.
HesAKeeper on Brown