Well, actually, since Cambodia was neutral at the time, he was legally an "Internee" in Cambodia and not a POW.
Under international law, when belligerent forces end up inside a neutral country and are "caught" by the neutrals, the neutral have an obligation to keep them inside the neutral country until the war is over. However, since the neutral country wants to stay friendly with both sides, the treatment during internmemt is usually Club Med or as close to it as wartime conditions will allow.
During World War II, many damaged U.S. aircraft were flown to Switzerland so that they would not crash land in Germany. All those American airmen were "Internees" of the Swiss until the end of the war unless they "escaped".
As you can see from the link of the Swiss Internees Association Website, these guys did not have a "Stalag 17" experience........."Am wondering if any Internee from the Palais Hotel or Bel Air Bar winter of 1944/45 remembers a young chambermaid/waitress whom you nicknamed "Betty"? "
An Internee can brag about being on the mission, about the combat and about his service but, when an Internee meets a "real" POW, it is best not to brag about his internment at the Palais Hotel and "Betty" the waitress. :-)
One amusing aspect of the Swiss internment was that the town chosen as the internment site for American airmen was right next to a Swiss resort popular as a German R&R area. So, Amerticans and Germans in uniform would bump into each other on the neutral Swiss streets. The Fourth of July was celebrated by aiming fireworks and rockets at the German consulate. :-)