USS Sampson, DDG 10. Vietnam era, out of Norfolk, Virgnia, so never anywhere near Vietnam.
I and the rest of the crew functioned as a unit. We couldn't call 911,, and we hd no doctor on board. We each had routine duties (I wasa cook), I was also a phone talker in after steering when we were at General Quarters (battle stations), and stood watch on deck with a .45 pistol while in foreign ports.
We functioned as a unit, all 400 or so of us, to carry out the orders and missions we were given. That was demonstrated during the Six Day War in June '67; we sat in the heat of the Mediterranean off the coast of Israel, not knowing how long we would be there at General Quarters, and there was not one complaint. We had a job to do.
We were commited to following orders, and had no say in what we were doing. I think each of us were hoping that our efforts would somehow have a positive effect in the world.
Anyway, that's a look at my experience; I know things are different for your son; I truly wish the best for him.