i don't think there is anything he can do in a criminal proceeding, i don't even know if there is any gorunds for a defemation suit in a civil proceeding. How are you going to prove she has said every word that you are accusing her have said. That said, the limitation period of a defemation suit if 1 year, if you realised what she started doing was more than 1 year ago, you are out of time anyway.