Stolen valor?
Heap big trouble for him if true.
My friend is 62 and when he was 17 the Vietnam war was over.
The US Embassy in then-Saigon (now Ho Chi Minh City) had a Marine Security Guard company (Company E) guarding it up through the evacuation in 1975. This was probably the largest single concentration of Marines remaining in country after the pull out of Marine combat units several years earlier. There were some other small Marine detachments in country principally involved in providing support to the South Vietnamese. (For example, the Marines in the advisor group made famous by the late Colonel (then Captain) Ripley’s action to destroy the bridge at Dong Ha.)
Age 64 now equals being born in 1954. That makes him 18 (age of enlistment) in 1972 and 21 in 1975. So he could have enlisted during the period of the US involvement in Vietnam and be considered a Vietnam era veteran.
(To be a Vietnam veteran (e.g., actually served in country) is another thing entirely. By early 1973 (the earliest he could show up in South Vietnam assuming an 18th birthday/enlistment in very early 1972), there were only a relative handful of Marines in country. Given his probable low rank (PFC-LCpl?) at the time, Company E is the logical first place to look since the company probably had well over 100+ billets for those ranks.)