She will get written notice of a court date. If she knows the family court that is dealing with this case, she can call and ask if there have been or is there any court dates coming up. If she remembers or has her case file, many courts are online and she can look it up herself by the number. It will give you basic info, court dates, judges name.
Maybe he filed for some type of govt assistance and the state is looking for both parents to pay them back or he can just be asking for it to be reopened. If the kids are still underage, he can ask for a modification and a reason why things have changed from 2006.
The written notice can be a mailed letter here for child support
, so they can use the last know address and it is considered good and they can have a court case.