[stylin19a]

Seems dogs and dog handlers in VN were scarce and elite.

Perhaps you could contact names in some of these links or look thru the comments to see if anything matches up with your friend.

Maybe start here: one could lead to another etc...

https://blog.togetherweserved.com/2023/06/08/the-dogs-of-the-vietnam-war/

or maybe here

https://www.vvmf.org/topics/Dogs-of-the-Vietnam-War/#:~:text=The%20German%20Shepherd%20Dog%20(GSD,widely%20used%2C%20primarily%20as%20trackers.

https://www.nytimes.com/2017/10/03/opinion/the-dogs-of-the-vietnam-war.html (pay wall)

Your friend really sounds like one of these...(5 man teams and their Labradors)
Could a generic DD214 mean ...CIA ???

https://www.legion.org/magazine/214896/vietnams-combat-trackers (clouded in secrecy)

good luck...If I can help dig, let me know via PM.

[Melian]

[Wegelhof]

Seems dogs and dog handlers in VN were scarce and elite.

Thanks I will check the links out. Oddly enough I know the dog’s name. TEX. And he handled a german shepard. I was think three letter agency as well. Anyway thank you I will continue digging.