Mental illness as an autistic child.

This is out of left field, and maybe not helpful in any way, but you might consider a brain biopsy to see if he has some kind of brain infection.
I'm not suggesting that has anything to do with the autism, but certain brain infections can cause behaviour that is considered psychotic, and they are treatable. It might be a complete waste of time, but I'd look into it.

Our oldest is autistic, but very high functioning. We have been blessed with help throughout his life, though there were many times we had to fight the school system for what he needed.
Early diagnosis, some good doctors, ABA and other therapies, social story boards and other strategies helped moderate his problems and have kept high functioning. While there were many struggles along the way, we've been blessed that he has never gone to some of the terrible extremes many have experienced. He's 24 now, and we don't know if he'll ever be able to live on his own, but he is relatively self-sufficient. He still isn't very good in social situations, but he's much better than he was when he was younger about blurting out inappropriate, insensitive, or otherwise embarrassing statements.

Praying that you find competent doctors who can help him, and are willing to take the time to do so.

The program I’m trying to get him into, at Children’s Hospital in Denver is pretty comprehensive. Everything is on the table at this point. It’s attack it now or lose this war. So left field isn’t left field anymore.

side note. I watched Kenobi and forgot to take my Unisom. So it’ll take a while for it to kick in. I used to sleep so well that the Army diagnosed me as a hypersomniac and even discharged me after ~8years. No complaints, it worked out well for me. But here I am unable to get to sleep on my own anymore because I hear every single creek in the house that makes me think my son is up and perhaps thinking of eloping. Last week he got to the back yard before I reached him. Even with unisom in my system, I’ll wake up if his bedroom door creeks open. I’ve got locks on every single window in this house. A few months ago, I didn’t have the screw type lock tightened down enough and he got out and onto the roof of the house from his bedroom window. No harm caused but now I sleep a little less. That lock is much tighter now. God forbid if we have a fire in the house.

On the plus side, because of all of this I’ve gotten A LOT more patient over the years. I firmly believe patience is a muscle. With the workout I get everyday, I’m practically Arnold Schwarzenegger at this point.