The Respondent should meet with a divorce attorney to review the options available. If the Petition was not filed in the correct court, there are some objections that need to be made before an Answer to the lawsuit is filed.
Typically, responding to a Petition in a custody case is as simple as filing a one page Answer. The Answer needs to be filed by 10 a.m. on the first Monday after the expiration of 20 days from the date the Respondent was formally served with the Petition.
If a timely Answer is not filed by the Respondent, the Petition could go to the courthouse without notice to the Respondent and take a default judgment against the Respondent.