I teach a student with Reactive Attachment Disorder and I need help

Special Ed. Teacher here.

This year I've been assigned a tough caseload. But my most challenging student is easily the student with Reactive Attachment Disorder and possibly autism. I'll call him Jake.

Edit: He's in middle school, btw.

To protect his privacy and my own, I can't give many specifics. This student is chronically online and I wouldn't put it past him to Google situations he's caused in my class.

Some vague descriptions of the things he's done this year:

-Repeatedly jokes about pedophilia and teachers who have been arrested for it. It makes me uncomfortable that he does this, obviously. The only saving grace here is that he has thrown it around so many times, including calling multiple teachers pedophiles last year, that everyone knows he is just being rude and it's not a serious accusation. Thoroughly documented and I'm not really concerned about actually being accused. Fyi, I have informed his adoptive parents and they have informed his counselor. They are taking it seriously and have started investigating whether or not this is just shocking humor or a more serious part of the Jake's history before adoption.

-Waits for the perfect time to drop rude or shocking comments to inflict maximum damage. When he wants to say something awful to me or in general, he will hold off until he has an audience and the room is relatively quiet.

-Constantly mocks and shit talks certain students. We have dealt with it. He isn't just getting away with it. But even after consequences, separation from the students, and punishments at home, he doesn't stop. He's hung up on hating a couple of kids in particular but will generally be rude to whoever if he wants to. One of these kids is a scrappy kid from a rough school and I could totally see it ending in punches if we don't manage this.

-Absolutely refuses to share any serious thoughts. Even when asked what kind of support he needs, what kind of rewards would motivate him, or what's bothering him, he just gives ridiculous answers in a high-pitched voice or walks away. This kid wants no part in coming up with solutions and won't even engage in a conversation about his behavior or even the behavior of others.

-Speaking of his high pitched voice, this is the voice he always uses to say rude things. He has his normal speaking voice and then he uses this higher pitched voice when he says things that are rude or shocking. Like he has two different brains and one wants to be mean.

-Last year, he kept a list of times he felt students and teachers had broken the code of conduct.

-absolutely hates special Ed. Hates me for being a special ed. teacher. Reminds the other kids in my class that they're "special" constantly.

For the record, all of these things have been addressed many times. The school has been supportive, the parents have been supportive, and everyone knows that this behavior, if continued for much longer, will likely result in a change of programming for this student. He would be placed in a more restrictive setting.

This is kind of my last ditch effort to see if anyone has ideas, because this student is on the verge of leaving my classroom. If there is anything I can do to make it work with this kid, I would do it immediately. He's smart, witty, and unfortunately very funny in a South Park kind of a way. But he's raising hell every day and he's the first student I've had where it feels like I can't connect with him at all. And not for lack of trying.