Q. He will be able to file our son by providing proof of court order?
A. No, unless that court order is dated before 2009 and contains certain language.
As explained above, the IRS does not honor court orders, it only goes by it's own rules. If you file a competing tax return, claiming the kid, the IRS will honor your return, not his. His only remedy is to take you back to court for sanctions. You would, most likely, be found in contempt of court.
