Please, forgive me if I am wrong and truly know I sympathise deeply with you but here's a sad thought.
I don't think it may have mattered what you had said or what the subject was. I can identify deeply with your Vet, God help him. I have a similar kind of PTSD, It is literally often like a huge build up of static electricity or a tornado that's cycling up and up and up in force I guess, just waiting to blow.
Often, at home for me, it all builds up internally, and then, over something trivial, ironically, like a word or the way something is said or relayed to me or a suddden noise, then BOOM !! Off to never-never land. Not violent thank God but loud and pretty frightening to behold to the unfamiliarised who don't understand PTSD. You remember Lee Ermey's character Gunny Hartman in FMJ and in his repreise in the Frighteners? It often gets said at home that's what I am like at my worst. I am not proud of it, i am deeply ashamed to my guts. I can't justify it. It is devestating and will no doubt destroy the happier, domestic part of my life that I desperately need and make those thoroughly miserable around me who will most likely, ultimately leave me and who could blame them. it took me years of self-watching to even get to know it, to feel it coming, to even try to tame it. I confess that literally, I have to carry a lawyer's number with me at the very worst times, we call them solicitors over here, in case it triggers in public and I get 'detained', although, thank God, law enforcement over here have great sympathy for PTSD God bless them. Add to that my guilt as a Christian for even acting this way at all. God is one friend I can't afford to lose.
I have learned through this happening hundreds of times now that for me it is honestly the heartbreaking and soul destroying inability to be able to physically go back to the actual situation, the root of it all, that stinking Godless moment - to intervene, to save, equalize, set the garbage straight, even the odds, change things, make right, get an answer, help my brother etc.... The kind of massive negative force and sheer internal pressure that kind of denied living generates could and should never be underestimated or ignored. It is a constant struggle. Go easy on the guy, go easy on yourself. Sometimes there are just no right words to say. In the light of what some of us have seen, words are often useless. Sometimes, just the precious joy of having another human who loves me, being beside me in the same room, even with them knowing all the horror of my experience that they wan't to be there with me by choice, that is a miracle, that is a miracle.