In relation to is it PTSD or not this is the way I see it: PTSD is about the diagnostic criteria and even then different people will present in different ways within those. A big part of PTSD is feeling unsafe and having very high levels of anxiety.
A spin-off of having high anxiety and feeling unsafe is various unhelpful ways of coping. That goes for those with PTSD but also those without PTSD but with high anxiety or who feel unsafe. These tend to be a way of attempting to manage and feel able to tolerate intense emotional states. Typical unhelpful attempts at coping are addictions (drugs, alcohol etc), OCD (ruminations, obsessions, compulsions), controlling behaviour, eating disorders, self harming behaviours, too much dissociation etc.
So it is not going to be PTSD but it will be fairly common for a certain amount of those with PTSD because of the terrible feelings of lack of safety and the intense emotional states that come with it.
Things can almost verge on delusions sometimes with conditions such as OCD, eating disorders etc. If we allow something to continue unchallenged we can actually be saying to someone that what they think is accurate and reinforce the delusion. Challenging needs to be done non aggressively of course!
But it sounds like the first step for your guy will be getting some sense of self awareness and taking ownership of his own issues!