I suggest you post up his e-mail address and get everyone to send an e-mail to him!
Hey xx (insert his name),
I heard you have been threatening my bro (insert your name),
Not something I would recommend, we come in numbers and we don't take threats lightly.
I feel you owe him an apology,
Your move and this won't be a stale mate.
If you do this, let Puddle Monkey write his own e-mail, that would freak the shit out of the poor guy and make him realise he don't want to be dealing with no mental patients.