[gallerytungsten]

If it's allowed in your jurisdiction, I'd suggest calling him and recording the call. Write a "script" beforehand of the things you want to say, and have a fallback line such as "I'm not sure of the answer, I'll have to follow up with you on that" if he tries to get you to admit to anything. Meanwhile, try to get him to over-reach in his claims and statements.

You might wind up getting some useful ammunition for later use; or if nothing else, a hilarious recording for further public shaming.