Yeah, SoG!Stephen gets put on the right track. (TARDIS!Stephen gets...better, by the end. But he can't be fixed until after he's traveled with the Doctor at age 44, or it would cause a paradox.)

And nobody should ever have to continue being sick in order to entertain people. The ones who care about his disorders and not him are in for a disappointment. But I'm confident he'll find a niche that he fits into naturally, and he's got the talent and the charm to pick up a new audience while he's there.