Is he a practicing attorney? WOW!
I still stand by my advice of either going ahead with the lawsuit or send him the letter as I suggested. I think the key is that you need to point out in the letter that you know he is breaking the law. It is "just" a civil matter, but still... He may be less intimidated by a letter than a non-lawyer would be, but that way if you DO wind up suing him I think it strengthens your case and weakens his.