IMO, there's nothing miraculous in the fact that KCC listed the wife and kid on the IL, sorry to burst some bubbles. They're listed on the form because the husband included their DS-230 forms with his own, KCC is required to show that the applicant has indicated he has family members and he wishes for them to benefit from his selection, KCC cannot ignore the request, void his selection or directly disqualify him. However, I'm willing to bet that the file has been flagged or will be flagged before it gets sent to the applicable embassy to show that the selectee claimed to be single while married with child.
The application process was and still is an electronic one. The pictures used for the process is filed electronically, so it does not make sense that an applicant can claim he failed to include his wife and child because he was based in another country and could not access them. I'm 99% certain that the application will be denied, but if the guy wants to continue processing on the 1% possibility of being approved, I wish him the best.