It sounds like his brain is getting flooded with emotion, which physically cuts off access to the thinking/rational part of the brain, the frontal lobe. Many call this amygdala hijack. Once he’s flooded, nothing you can say will extinguish the intensity. In fact, it will only escalate and prolong it. The brian needs time to calm and recover. Some need someone to sit with them quietly for this. Others want to be completely alone. He clearly needs your presence, but just not to engage until he’s calm. Sending him to his room and shutting the door feels like you don’t want him.
As for using Ross Greene’s CPS model, it’s important that everyone is calm or it just won’t be successful. Always have that conversation when everyone is calm. Otherwise, let him know that you want to help but you both need to take a break to calm down first.
Be very careful of the language you use when talking to him. As parents, we tend to use accusatory and judgmental language with our kids without even realizing it. You used words like “unreasonable,” “extreme victim,” …
Also, make sure the conversations are truly collaborative. Yes, boundaries still matter, but it must feel like give and take to keep a child engaged and for the process to be successful.
My mantra in the tough times is “Your child isn’t giving you a hard time, your child is having a hard time.”
ADDitude Community Moderator, Parenting ADHD Coach & Author, Mom to teen w/ ADHD, LDs, and autism