First of all, your brother deserves the absolute world and I'm truly sorry to hear what he has suffered.

There is no 'right' or 'wrong' advice... I can only say this.... he will be fighting his demons, nightmares, of what he will probably never want to share but will subconsciously re-live. Entwining the present with the past.
I've suffered PTSD and it's a living nightmare - literally.

Always remind him that what he did, was an honor. What he fought for, was for his country, what he went through, is a warriors journey and what he faces now, is only what he has already conquered. I can only imagine what your brother has 'seen' .... but he doesn't have to re-live it by talking about it or storing it in. It all comes out eventually. Just remind him of his bravery. He's a hero. But even the best fall down sometimes, and he's still here, because he's a fighter.
Remind him that he is not his demons. Remind him that even though he can not change the past, it was not his fault. Remind him, that he is loved. My heart goes out to you and your beautiful brother.
PTSD - Proud. Tough. Strong. Determined.
Xxx

Thanks for the lovely comments

I got it from seeing my stepdad murder my mom by shooting her 5 times in her chest and then the coward shot himself in the head, while as a 9 year old I stood there and watched the entire thing.
I was sent to be with the rest of my brother and sisters but I was the youngest.
they were told before I got there not to talk about, tell me nothing, I never went to counseling. I kept asking for her and I was told sh's fine you will see her soon; Well I found out months later and the answer I got was were going to buy you a bike????WTF ; I never felt like any of them my entire life they all ran away I was to young, and this guy I was told was my father was never home, at age 46 I found out through a friend they all new and the man I was told was my father never was. MY biological dad died 1 year later he was a NJ state TROOPER and was killed on the job. SO my who life was a lie, cousins are not they don't have the same blood, grandparents,brothers. I ended up with a nervous break down.

like proud tough strong determined have a good day

i found my vet center provided the most help j am an army vet he can ask me anything he can also friend me on facebook (mark lenfest)