The man has PTSD. The signs you describe are consistent with PTSD. You and your coworkers need to take your concerns to human resources and avoid discriminating against this man based on his disability and his military service.

If you wish to advise him, advise him to contact a good employment lawyer. You have knowledge that he was not promoted because someone disliked him. This bias may be discrimination based on disability and pr military history. Do the right thing.

The man as you describe him has ptsd. He does what he does (keeping war imagery before him, enraging himself with images of child predators and the histrionic ranting of television news commentary) to keep his catecholamine levels up and his opiate receptors filled.

He needs help. He needs expert help. Do not muddle in his situation. Adequate help is hard to come by.