Am I wrong for reading that Jorah scene as the last time we'll see him in the show?
I don't think we're literally meant to follow him searching for a cure. I think it was Dany's way of giving him something to live for instead of just giving up and becoming an alcoholic and killing himself.
In this show, people normally can't just disappear forever, especially if they are important characters. We need confirmation of important characters deaths or fates. For example some people we haven't seen for a few seasons are about to reappear this season.
We may not see Jorah the rest of this season or even season 7. But we will see him again. Even if we have to wait till season 8 to see him. He has a part to still play in the story. And his GREYSCALE, has a part to play in the story as well, I think.