I’m not familiar with NJ law, but would think that “disorderly conduct” is a misdemeanor and not a disqualifier for owning a firearm.
If so ... the point is, they took his guns and they refuse to give them back. Sure, maybe he can buy more ... it's still theft under colour of the law.
THAT'S why I'm invoking the method of Dr. Tarr and Prof. Fethers.