I really feel for you mate I really do. In my opinion PTSD in those exposed to war etc, should be presumptive and always assume that a person that has been in that environment has the potential to suffer from the effects of PTSD. I see it no different to say a firefighter, where it should be assumed that if they get cancer it is pressumed that it was caused by the job, even if they were exposed to that environment for a short time.
I wish you the best, I really do