Oh, he may have PTSD from some damn unfortunate life event or another, or at least honestly believe he does and have convinced himself it's the cause of all his woes, it's just laughable that DTG would be a vet.
PTSD can be totally disabling, unfortunately it is also incredibly over-used as a diagnosis and it's a spectrum disorder so that the bare diagnosis people will tell you runs the gamut in actual effects from totally incapacitated to occasional insomnia and the odd dark thought. Just like autism or Aspberger's, it's something that can range from someone being an unemployable basketcase to high-functioning people who just have what used to be called 'A few quirks.' The military medical system in particular is biased toward finding it, in large part because that's what they look for and have a system to handle (The old 'When all you have is a hammer, everything looks like a nail' thing). In a big way it's a trap for the patient, once diagnosed it opens up a lot of treatment and drug access, in fact the military docs went 'way overboard prescribing drugs for it for a long time, to the point that some of the more feloniously-minded soldiers started selling off their meds to friends and neighbors with plenty left over for themselves, establishing a military opioid problem which was miniscule beforehand. Another trap in it is the whole victim mentality thing, because the marginally-affected but poorly-motivated got an excuse for their other shortcomings and turn it into a crutch for failure, and then there is the whole problem of failing to realize that getting a psych diagnosis is something that can come back to haunt one much later in life, in unforeseen ways, and close off many paths that would have been open.