You know enough about guns to know that Dishonorable Discharge is one of the questions they ask when buying a gun from an FFL licensed dealer.
He must have bought it second hand.
I was being a little sarcastic, I ran a gun store for several years, and have been a gun guy my whole life, hunted from Alaska to Zim, shot trap, skeet, and both international styles of them on college teams as well as shooting a handgun competitively.
I was pointing out that he could not legally own a firearm, court martial for a felony, dishonorable discharge as well. I’m pretty sure we don’t need another law that he’ll just break.