So I am a veteran with a degree in psychology and I am dealing with another veteran at work who is a real problem. My friend has defended him by saying he has PTSD but I am not sure.

He is obsessed with watching violent videos of people getting blown up which to me is the opposite of avoiding anything related to an original trama characteristic of PTSD. He is very abrasive with other people but I have gotten the impression that he was that way long before he joined the marines. He talks about his experiences in the military with enthusiasm and has openly stated that he would rather be in Iraq killing people because he enjoyed it. He is a hard line political conservative and will rant endlessly against democrats and conspiracy ideas if you let him. e.g. Obama born in Kenya and global warming not existing. He doesn't get along with a lot of people at work and even hates one guy he barely sees for no apparent reason. He is also obsessed with pedophiles and memorizes the faces of guys on the sex offender list in case he sees them on the street. He has a family but says he wont go on a family vacation without his gun. Everything in his life seems to revolve around either football, politics, or the marines but he has been out for about 5 years now. He just got passed up for a promotion by someone he doesn't get along with and has stopped talking to everyone socially except for what is required to do the job.

What is up with this guy? He is giving people the impression of the stereotypical "ticking time bomb". All opinions, advice and comments are welcome.