I'm usually a hard ass about stuff like this but the fact it was no secret he had a disability changes things.
It's lack of common courtesy and basic manners that gets to me and this boy wasn't being inconsiderate or rude. That's not to say I would have been thrilled to sit next to him, but I know I would have practiced some patience, accepted the situation, and try not to let it get in the way.
I know I make it sound easy when it was probably a much more difficult situation. I acknowledge that and don't know exactly how distracting it was. I think it's a bit much to be sickened by the OP, because it seems it was handled with as politely as possible, but that's just me.
On the seat change thing: I sometimes go out of my way to obtain the best seats possible and generally find it very bothersome if anyone requests for me to move even one seat down. Sometimes moving down one seat can drastically change one's view if there happens to be someone in front of you who obstructs your view. At 5'4" tall, just about anyone can, lol.
Recreation of original John Cameron orchestration to "On My Own" by yours truly. Click player below to hear.