Dad, citizen of and living in France does not appear at court hearing re child support. He is international attorney with law firm based NYC. What do?

There is not nearly enough information here to hazard a response.  Was this hearing in Nevada?  If so, what was the basis of jurisdiction over dad?  I suggest yoiu start with reviewing "The Basics of Family Law Jurisdiction" posted at http://www.willicklawgroup.com/child-support/, and then consider a consultation with a family law specialist well versed in jurisdictional law.