A Question About Taxex...?

My X husband is court ordered to pay for dental benefits for our children who reside with me [his idea] and I cover medical. One of our daughters got braces last school year, and her father has not paid a dime. He had told me a year ago that when he got his income tax return, that he would use that money to cover her orthodontia, but to date he maintains that he has not filed his tax return/some kind of 'glitch' in the system. The orthodontist has dismissed our daughter as a patient as a result of this. I am [reasons dont matter] unable to pay for her visits nor make adequete payments. Is there any way to find out if a person has at least filled their income tax return [ amount of return is not what I am looking for]? If anyone knows for certain, i would love some information before I file a violation in support court later today. Thanks much!!