Real talk, Bro men of the Internet. I've got a serious problem, and I'd love for some advice to ignore.
I've got two best friends. One is a hot artist chick, the other is a loving mental faux-Russian dude. Without going through all the bullstuff, the chick has come to hate the dude enough that she never wants to speak to him again. She told him straight up she never wants to speak to him. He, unfortunately, is a loving idiot. See, this chick has some pretty serious issues, and so sometimes she'll outright block people for a time. It happens, I get why, I'm not complaining about that. This dude believes this is one of those scenarios (and also believes some really incorrect and stuffty things about her), and now he's coming to me expecting me to write him a message that he can send her so that she'll start talking to him again (because people use me to do their dirty bullstuff).
Now as you might imagine, I of course was a key player in making the chick want to ditch the dude; the chick was already getting annoyed with him, and behind his back I told her the nasty stuff he was saying about her (I have my reasons). There are no heroes in this scenario. That said, if I outright say "she's serious", for reasons I won't get into that will tip him off and it's going to send everything to stuff (this dude isn't just mentally a lunatic, he's also a loving good fighter).
What's the best thing to say here? I don't want the two to be friends again; she doesn't need that, and he's been using her as a replacement for another girl that he needs to get over.
TL;DR: Guy is asking me what to say to make friend "forgive him", friend and I don't want that. What do?