I have read what Matthews has said. I don't believe it is actionable for Levin. Unless all Levin wants is a deposition--in which case, go for it!
But there's all sorts of plaintiffs out there, non-public figures, who'd have a case.
I think he made that threat after Chissy said what he said..he has given them all fair warning...I remember decades ago Carol Burnette actually sued Confidential magazine for slander and won...its possible. Now there are so many types of that rag, you cannot sue them all.