JJJ -
Just a thought. Years ago, I used to teach trial technique classes. One of my favorite parts was when the students would bring out their videos and watch them with me and a professional actor. We would critique them and go over what they were thinking, what they could have done differently, etc. Although it's not exactly on point, is it possible for Eeyore (by the way, I use this nickname for my own 13 year old but not on this board) to watch the tape with his counselor and discuss what happened at each point? I think seeing it might help him to comprehend how it appears to others. They could brainstorm steps he could have taken at each point to avoid D - like walking over to a teacher instead of just walking away and coming back.
My own Aspie son, now 19, discovered ISS after being attacked in school in grade 6 and fighting back. He lOVED it and would try to go whenever possible, LOL!
The Lego gun made me laugh as well. My 19 year old was almost suspended in middle school (surely the 7 circles of hell all in one) because he wrote "Anthrax" on an envelope. My now 10th grade honor student was almost suspended because he told the school psychologist that when he was grown he was going to come back to school with his army and show them. When the psychiatric asked if he had the army with him, he said "If you see them, you're crazier than you think I am!" I fought both suspensions.
Does Eeyore have a "circle of friends" group? Maybe they can set one up for him or get him a line buddy. Maybe then D won't bother him anymore.