I think this is going to go beyond PTSD.
I also am a military spouse, military mother of 2 who serve this country, daughter and granddaughter of those who have served, so I understand the care that is available during and post military.
There can be many reasons why someone isn't getting the care they need. There are wait times, provider shortages, and red tape when dealing with the VA. I can imagine for someone injured as badly as he was, he could need a lot of long-term care and year after year trying to deal with the VA and often getting told to jump through all their hoops over and over again, it can be draining and result in people giving up. Not saying this is what happened, or this is an excuse, but sometimes it isn't as easy as they have help available. It can be cumbersome to get the help and for a Vet with PTSD and possibly other mental health issues, they aren't always thinking like you or I or someone rational would. I've seen it with my own family members and friends. Having a support system is KEY.. someone to advocate for you when you get tired of it, someone to encourage you to keep going to appointments, to make another one, to call and try again, to keep fighting for yourself. It can wear people down, so they just give up.
Now this is all my opinion but based on the many lawsuits he was filing for things that seem very much made up or imagined by him, it sounds like he is paranoid and possibly having something else mentally going on other than PTSD. It is not PTSD to think people are poisoning you or trying to get you because they are LGBTQ and you are heterosexual.
Reading that one court document with his parents listed and their response was they want him to get mental health help. There needs to be an easier path for someone to be put on a 72 hour hold. It sounds like he needed to be in patient getting some intensive care to figure out if he needed meds or what exactly was causing all this paranoia. It was so very documented in all his lawsuits and instead of just dismissing them, someone should have been able to do something more for him. He was a ticking time bomb.