Arandor
Auto-translated
Well, considering that there must be a way to heal (it's clear why), it's most likely that it will become available after helping the Mist, so my vote is obvious. All other options are possible, but less likely. I doubt that the fake Sharon knows anything at all; she's probably just a pawn who has to play a role, and other people will be advising him. He probably doesn't even know about the cure, where to get it, and so on. And if we return to the lair, we'll probably find nothing again, or maybe even people.
Be strong. Believe