Apparently this vile idiot former Marine was asleep in his classes about what happens to you when you get in trouble with the civilian laws. Unless things have changed, he will go through the civilian process and then be immediately transferred to the custody of the military for their dispensing of military justice. When they are finished with him and his military sentence, he gets to go back to the civilian sentence and they are not concurrent.
He will not make it out of the Brig. Stealing from soldiers, er Marines, in a combat zone is not a very enticing enterprise and usually ends in a punctuation mark for your future.
Because of the nefarious nature of the scam, I have a feeling they’re not really a Marine. It’s part of the scam.