The IRS follows federal law, which overrules state court orders.
However, this sometimes means that what you can claim legally on your tax return, will violate a court order. The IRS will not care, but the family court might care very much.
Generally, if you have a parenting order, you can't just decide to ignore it if the situation changes, you have to ask the court for a modification. If you don't ask for a modification, the old order remains in effect, because that's how courts and court orders work.
You need to consult with an attorney who can review your specific facts and circumstances.
