Jokes aside I wouldn’t do this if I were him. He’s probably going to be in prison suspected as a foreign infiltrator.
https://www.bbc.com/news/world-asia-66219603.amp
He apparently got in a fight with a Korean civilian and at least was disorderly (if not combative) when arrested. No idea what type of penalty that would get someone at a U.S. court martial, but prison and a dishonorable discharge (making gainful employment extremely difficult) are probably on the table, maybe guaranteed.
No idea what I’d do in that situation, but even knowing he’d be detained for a while in the DPRK it might look better than the alternative.
Of course, there’s a big chance he is trying to infiltrate the country, and this is pretext. He’s 23, not some kid right out of high school, which to me suggests that’s far from out of the question.