Oppositional Defiant Disorder (ODD) Support Group
Oppositional Defiant Disorder (ODD) an ongoing pattern of disobedient, hostile, and defiant behavior toward authority figures that goes beyond the bounds of normal childhood behavior. When a child cannot seem to control his anger or frustration, even over what seems to be trivial or simple to others, the child will often react in violent or negative ways to his own...
https://www.psychologytoday.com/blog/the-human-equation/201104/children-who-are-cruel-animals-when-worry
I hope this helps. Take care of yourself.
I'm glad we've already done the right thing by getting him professional help, but it doesn't seem like enough.
http://www.thefamilythathealstogether.com/pandas-syndrome-how-we-healed-it/