PTSD does not manifest itself (for the most part) like a Rambo movie except the part when Rambo bounces down to see his buddy and the behavior change when he finds out he is dead.
A dog is not gonna prevent the fake nuts that many claim. There is no switch that gets flipped during a PTSD episode where you find yourself in the combat zone except in a semi conscious state like being woke up or a traumatic event like being attacked.
Most people with PTSD simply withdraw. I hear more Karens and fruit loops slinging the term around and they aren’t even combat veterans. “I got PTSD because he wouldn’t use my proper pronouns”