I wouldn't drop the bomb. I know how tempting it is, especially considering her attitude towards you lately. But I'd take the high road. Which is be sweet, sweet, sweet. Her rantings will only make her look like the idiot in the end. If she truly has a personality disorder, then my belief is that she won't take your info with a grain of salt anyway. She'll deny it, say you're an apostate, and probably rant some more. Why bring out her anger when she probably isn't going to listen anyway?
Maybe you can send something to her anonymously in the mail. Maybe a spoof of questions from the readers with a question about the NGO/UN thing. You can say whatever you want because you're the author and she won't know that.
I can say that I've thought about doing something like that (the anonymous question from the readers things) with my folks, but don't know if it's worth it. We haven't been in touch in over 8 months now. My life's been pretty peaceful...and I think I like it that way. I think I'd rather let sleeping dogs lie.
Andi