It would not be the first time that the visible aggressor was in fact the victim of a long drawn out teasing campaign by a group of bullies, and girls can be bullies just as easy as boys.
One of the best bits of fun seems to be to goad someone until they snap and then let them take the blame for it all.
Been there, done that, have the t-shirt.
That being said, I have seen the kids first hand pushing his buttons on the school yard. There are so easy to push it's hard for them to resist. We are working with both the school and some mental health workers to make the situation more livable for all parties. I appreciate your concern, and I do understand that play-yard aggression is often mis-construed. That is most definitely part of this situation.
School can be hell if you are standing out in whatever way, and cause and effect can be hard to separate sometimes. Night terrors could be causing trouble in school, school trouble could be causing night terrors just the same.
I wish you the very best of luck with this, and I hope that it will all come to a good resolution.