Reporting a site? slander?

Only way that he could get a lawyer and sue is if he has definite proof of actual damages directly due to that site. He would also have to prove that what was written was 100% not true and written for the sole purpose of malicious harm towards him. If he has definite physical proof of all these things, then he can talk to a lawyer about issuing a cease and desist order and law suit to recover the actual damages that it caused. He could include the attorney fees in with the rest of his actual damages too.