Think the other solution is easier by simply phoning him up and telling him to back off. The whole point is to make him realise this goes beyond just trolling on the internet. That you're actually harrasing people in real life and that they can get to you if they want, instead of thinking you're safe behind a monitor. Once shit gets real it's suddenly not that fun anymore to "troll"
People like that do those things for this reason, they want this reaction, it gives them the sense of success. Do you honestly think anything you say will affect this guy?
And calling threatening him doesn't help any of you at all