The big problem they are not in town. Even if they go back to Sandpoint, there is no high level cleric at all. So they are on their own pretty much. Yes, they can get a +4 save with treat disease and their cleric can negate some constitution losses with Lesser Restoration, but Vorel's Phage has DC20 which is very hard. Also ghoul fever from ghast has DC 16. They are 4 of them: sorcerer, cleric, ranger, bard. All of them are sick, 3 of them with Vorel's disease, 3 of them with ghoul fever, 2 of them with filth fever. It will be hard to cure them, but I will obey to rules and we will see what happens.