I can only give you a possible logical explanation why he is unappreciative. Like you said he is trapped in his own world and there is no escape from it. I am sure within all the chemical imbalances in his brain there is a part that is incredibly frustrated that he can't do things by himself and he lashes out at you because you are there.
There is a direct correlation between empathy and suffering. If you suffer you have empathy for others. You have more empathy for those that suffered in the same way as you did. Suffering could also mean your situation where you see your child suffering and you can't do anything to improve it, just mitigate it. You're playing the game of life to only not lose as is he. His disability prevents him from winning.
The point is that I have associates that were born well off, no neurological disabilities, raised by good parents, went to good schools, had healthy environments, had healthy diets well relatively to most of the world, and are successful. Yet they have that mentality of "he needs to just pick himself up and do something with his life". Because they were born under all the right circumstances with the right genetics success was simple. Most of them had superior skills in some category that is accepted by society as a positive. Like high social intelligence, high enough I.Q. to get educated, excellent brain chemistry that lowers anxiety, etc, etc, etc. They just don't get it.
I ask them how their life was just like that list above.
Then I tell them "do you realize that 1 in 1000 people live like you do around the world? You aren't rich but you are upper middle class. You have everything available for a good life a rich person has." Sometimes they see the light for a day then revert to their narrow minded thinking. Like in your case with the courts. The judges do not understand the level of impairment your son has, I do. You take away my wife's anti-depressant she will sit in a room all day and read doing nothing. Without her ADD medication she can't work properly and gets overwhelmed. As you age it gets worse because the brain mechanisms don't work as well.
As for me... The only bad part of my life was that I was raised in a slightly negative environment and I think I had ADD as a child which I overcame.... or I was bored at school, not sure. I am incredibly intelligence, low stress, and in my adulthood I because highly organization. I have very good social skills because I taught myself to be better than average, no depression. But I read a lot and witnessed the growing up of my child and the swings of my wife. Now I have this perspective. 20 years ago all this wasn't in my head. I knew nothing, didn't think of it. All I knew is that I found work I enjoyed and was challenging.
So you have a whole society of people that are in charge that have a good life due to the roll of the genetic and environmental live that have no understanding of this kind of disability. Unless a disability is right in their face like a blind person, a paralyzed person, they just don't see it. Mental disability doesn't exist in their brains. These mentally disabled people are lazy in their heads.
I did speak with a lawyer about disability. She is a specialized lawyer in it. She told me she constantly has to explain to the courts that just because someone graduates high school with good grades doesn't translate that they can function in the real world. Social Security always denies initial claims for autism. You have to go to court to force the issue.
My opinion there should be facilities, group homes, where people like your son can go and get proper help in a healthy environment. Not saying your environment isn't good but I am sure you are stressed beyond belief. Even I get overwhelmed here. My son isn't nearly in such a disabled state as your son. But I go two of them in the house. I run everything like you. Groceries, bills, cleaning, walk the dog, make sure schoolwork is done, medication, remind my wife of appointments. At least for her work she is organized. It's not even that each task is difficult, it's just that there are so many I have to constantly remind myself of and I use a calendar. I am sure it's the same way with you. Constant to do list and you can't stop or it all falls apart. Don't even get me starts on the cluster **** between the doctors, health insurance, and pharmacies that i have to stay on top of for their medications. Then there is my mother who is an hour away and refuses to move into assisted living even though it's all setup. Then there are 2 old lady neighbors who constantly ask for my help.... I just realized why I am overwhelmed. Too many people asking for help and only 1 of me.
Anyways I feel for you and your situation. And it sucks your son is stubborn to boot. My son realizes I am much wiser than he is and listens to me on health issues.