School not coping - parents fault?

Hi. My son is 8 and in Y3 and is high-functioning ASD with SPD and separation anxiety. He attends mainstream school and has an EHCP and 1-2-1 support throughout the day. The school have just called (another) emergency meeting, this time involving the CAMHS service and a child psychologist and this morning the SENCO called me into her office to tell me that my son is now causing significant disruption in class and that his teacher cannot teach effectively as a result. Apparently, his behaviour is now impacting the learning of every other child in his class.

My son benefits from a supportive family, an active and healthy lifestyle and we rarely see challenging behaviour outside of the school setting. Both his mum and I ensure he completes all his homework and he is very bright. Unfortunately, the school appear to be unable to engage with him. He has been excluded from next week's school trip, he is not progressing or trying to learn and just failed a maths test that he passed a year ago. All he wants to do is sit in the reading corner and read books. When he’s made to participate with the class he acts up. The teacher is newly qualified and his 1-2-1 has never supported an autistic child before and neither has received additional training.

I don't understand why the school is telling me this. It's almost as if they expect me to have a solution. All that it's doing is causing me significant anxiety and led my wife to have a panic attack. My son is already no longer invited to any other child’s birthday or on playdates anymore because of his behaviour in school, which is also causing us a lot of anxiety and sadness.

I have concerns about my sons anger and he often fantasises about harming others and writes stories that usually involve violence, so intervention from a psychologist is needed, however the school are basically dumping their concerns problems on us, almost as if saying ‘we can’t fix this so over to you’. It’s not a helpful position. We do so much for him at home (I've just built him a sensory room which he loves), it just doesn't seem fair that the school are asking us to fix their problem.

Does anyone have any advice? Is there anything I should ask the psychologist? Perhaps I don't understand the schools position - It's not like I have experience myself either! I don’t want my son excluded or moved to a special school. I just want him to be happy, and I am certain that right now he is far from happy when he’s in school.