Per Wisconsin state legislature:
941.2905 Straw purchasing of firearms.
https://docs.legis.wisconsin.gov/statutes/statutes/941/iii/2905
Child gun laws in Wisconsin
https://wisconsinwatch.org/2015/08/child-gun-laws-in-wisconsin/
He didn't purchase it, did he? How could it be a straw purchase?
What child gun law did he break?