I think he has a conflicted view of his time, he did not stay in the service afterwards and to this day I think he both regrets his participation in the war and is proud of it at the same time.
I think war, and by extension the military allows people (mostly young men historically) to push themselves and put themselves in danger, forming some of the most memorable moments of their lives. The problem is this often goes with creating some of the most traumatic moments of their lives, and they are forever stuck with the juxtaposition of those memories.
I've personally felt a longing for the former but not the latter and I wish there were more opportunities to gain those kinds of experiences and the camaraderie without having to do things you are morally opposed to. I've found myself looking into disaster relief work and things like that at times as an alternative but that might not be a realistic option at this point in my life.