He was an antisubmarine pilot, so he spent most of his time on the ship or flying over the ocean. He did put his feet on the ground in-country, but I don’t think one would think of that as “living in Vietnam” any more than I “lived in England” during a visit.
When my brother was stationed in England, he had temporary posts in Turkey, Romania, and elsewhere for a month or more. Is that “living in Turkey” or “living in Romania”? I suppose it’s simply a philosophical question.