This doesn’t answer your question directly, but MAD TV had a similar portrayal of Kenny Rodgers. Will Sasso used to play him as a child-like lunatic. I always thought the joke was that the impersonation was based on absolutely nothing, like Tracy Morgan’s Star Jones, or Family Guy’s Margot Kidder. In fact, Will Sasso actually explained that that was the joke by playing Kenny Rodgers straight in one sketch, and saying basically exactly what you said (i.e. “Kenny Rodgers really doesn’t act like that at all…he’s really a perfect gentleman…”). So anyway, maybe SNL is aping MAD TV’s gag.
What’s he going to do about it? I would think that because it’s obviously a parody, it’s considered protected speech. Hey-Hustler once published a fake confession by Jerry Falwell that he lost his virginity to his own mother in their outhouse. Falwell tried to sue-and lost because it was parody, and thus, considered protected.