Brian Dennehy was reportedly lying about having served in Vietnam. Not sure whatever became of that but it was going around maybe 15-20 years ago.
Does that make the movie unwatchable?
Yes, I saw that when I later looked into his story, mainly to see if he was still alive, and was very surprised by it.
Found this...
“He served in the United States Marine Corps from 1958 to 1963 in Okinawa. Wondering why you haven’t heard him listed in the articles favoring veterans in Hollywood? Probably because he lied about his service, claiming to have experienced horrifying combat in Vietnam, when in fact, he never set foot in Vietnam — not as a Marine anyway. Later, he publicly admitted to his deceit and apologized:
‘I lied about serving in Vietnam and I’m sorry. I did not mean to take away from the actions and the sacrifices of the ones who did really serve there … I did steal valor. That was very wrong of me. There is no real excuse for that. I was a peace-time Marine, and I got out in 1963 without ever serving in Vietnam … I started the story that I had been in ‘Nam, and I got stuck with it. Then I didn’t know how to set the record straight.’ ...”