If he has actually filed and it is contradictory to the court order the file a contempt motion.
If he files and the IRS receives two returns and catches the duplicative claim on the dependent child.
You both will he asked to file hard copy returns.
you likely will do better to let him know that you are filing a contempt motion. The courts don’t take kindly to people like him and will likely make him pay your court fees and may even sanction him for your time and energy.
