Well that's why he's talking to us from the past. He doesn't know we exist, he doesn't know who he's talking to. Technically, he isn't even talking and this isn't even his face. He is not just a ghost, but an abstract concept. He is a spokesthing of all soldiers, whose average experiences can all reliably be averaged out, based on the "serve and die like nothing" routine of military casualties, into being essentially a wasted life of fear and regret

So, really he isn't dead. He isn't alive. He is just an idea behind a picture, born from past atrocities marked by the deaths of many who wore faces much like the one that he wears here