his actions are his responsibility. While you may have been a nag or many other derogatory terms I won't mention, he chose to do what he did. No, you talking to his PO isn't going to save his butt. He made his choices; he will have to live with his choices.

What happens is between him, his PO, and if his PO violates him, the judge. While a PO can violate a probationer, it is up to the judge to revoke probation or not. All you can do is stay out of this unless the courts ask for your input.