Comment by Grumpy Old Snake

And not just whoever cast the spell on him--everyone who knows Jonan and finds out seems absolutely convinced that there's going to be a horde of angry and possibly powerful people after him as soon as word of his inability to cast gets out. I think you're right about his reasons for turning Jonan away--he seems downright terrified. (To be honest I'm pretty sure that's at least part of why Jonan's so, excuse the pun, close-mouthed about his situation. Sure, he's pretty prideful, but he also knows how many could take advantage of his situation.)