Actually, I just googled.
Al-Aqulawi's father did sue the government saying that Obama admins actions were illegal. The case was dismissed and the judge ruled that ONLY Al-Aqulawi himself has any procedural or due process claims. And he was blown to 1000 pieces. So, in fact, there is literally no way for for this to be challenged.
https://ecf.dcd.uscourts.gov/cgi-bin/sh ... 2cv1192-36