I don't understand that mentality. He isn't above or below any of them, even severe and non verbal autistics.
What do you mean by "above" or "below". In some cosmic, moral sense, it is fine to say that his life is not worth any more or any less than anyone else's.
In terms of some measure of competence and ability to interact with the world, there are lots of autistic people who are "above" him, and a lot of others who are "below" him. Many people on the autism spectrum are largely indistinguishable from non-autistics unless you know them well. Some are completely non-verbal and find it very difficult to take in any information or stimulus from the rest of the world. Chris very clearly falls "in between" these groups in a way that most people would find intuitive.
Chris also seems to have always been desperate to be seen as in the first group and has feared either being confused as or even associating himself with the second group. He wants you to see him as an equal the vast majority of the time, making occasional allowances for autism.
My armchair psychiatrist theory is that on some level he is a little insecure that he might be a little further down the scale than he hopes, and that's why he describes severely autistic people as "windows into hell". Some of it is somewhat understandable. Think about the school bus case, where he was unhappy after being changed from a normal bus to a special kids bus. Basically, he was shown two busses, one with a bunch of normal kids, and the other with exclusively kids who have something wrong with them. He was then told, "you can't crack it with the normal group, you are more like the others". I can understand why that would be a bit of a jarring experience.
If he is going to be ok with some more custodial solution, he is probably going to have to be convinced he is receiving some minor accommodation for his autism, as opposed to receiving the sort of help that a very severely autistic person would.