Another thing you could do is report his internet abuse to his ISP. Email a complaint & attach the emails from him to : postmaster@{whoever his provider is}.com/net (for example:
postmaster@yahoo.com). I had a guy send me a bunch of asinine email FROM HIS WORK EMAIL, I googled his place of business and called & talked to the manager... forwarded the emails to him & also complained to the ISP. Within 24 hours the OWNER of the company sent me 2 emails apologizing & they fired the guy. Your buddy could lose his internet service & maybe his job!