WMG / Yes, Your Grace

Talys wasn't looking for a cure for his sick wife.

Nothing in his on-screen behavior suggests that this king cares about his wife. When Eryk asks him about her, Talys brusquely states that the subject is none of his business, and later gets annoyed when it's brought up again. And he suggests that he expected Eryk to fail to keep his word, which suggests that he, in turn, was going to find a way to avoid keeping his word. So what was his game? He was looking for something else ... possibly personal immortality so that he doesn't have to pass his throne on to his heir, whom he views with nothing but contempt. This increases the tragedy of Ivo's belief that everything would have been all right if he'd succeeded in killing Eryk.