Same here, except my dad was a Green Beret Major. I don't know what his unit was. I was just getting to my teen years during the time he was there, and paid little attention to those kinds of details.
Our family was stationed on Okinawa, and I was constantly surrounded by the hustle and bustle of wartime logistics. I got so tuned in to things, that I could tell which soldiers were incoming, and which were on their way back to the world, just by looking in their faces.
Where I lived, and where I went to school, nearly everyone's dad was in 'Nam. Our moms did everything in their power to keep us distracted, and to keep us away from reminders of what our fathers were doing. I think we would have been a bit nuts, otherwise.
On those rare occasions when Dad would get enough time off to come home, we had to walk on raw eggs around him. As the eldest child, I think I had the best formed concepts of what my dad had been living with, but even to this very day, I don't really know what he lived through.
At 80, he's still reluctant to talk about it. Vietnam is a bit like his "missing 18 minutes" when he reminisces about his military career. For my part, I've never asked him to tell me about it. I wish I could, but I don't know that I ever will.
Find out your folk’s unit and when they served, important, you’ll be glad you did. They may not talk much about it but when you find out their units, surf the web and dig out the history of those units, then you’ll start appreciating them even more.
Regards,
Vietnam Studies U.S. Army Special Forces 1961-1971
Special Forces (United States Army)-Wiki page
You said you were stationed in Oki, so I'm thinking that he was part of 1st Gp. 5th Gp also made a up a large contingent of the mission in the RVN.