I just want you know that you aren’t alone in this. I can relate - our daughter is autistic with ADHD and PDA profile. Consequences like time out won’t work if he has a PDA profile - read Ross Green’s book “The Explosive Child” if you haven’t already. Medication for anxiety has definitely helped lessen the PDA aspect for our daughter. And don’t give those who judge a second’s thought - it’s just their own ignorance. 

“My Father” with Anthony Hopkins. I watched this when my dad was in the final stages of dementia and it was like watching my own life on screen. Absolutely devastating but a release for the ambiguous loss I was experiencing.