Purely conjecture, but I would guess that he would NOT get it back until and unless the final disposition is ruled in his favor. He’s either going to have a disqualifying conviction, or he’s going to be exonerated. If the former, he can’t have a gun, and if the latter, he can’t have it until he has been exonerated.
[comforting thought]Of course, you have no idea if he has or does not have a shotgun in his house.....[/comforting thought]