You make great points V. Why is your family therapist involved? What is the focus of their work? What model of family therapy do they use? Do they have experience working with children with neurological conditions?
Sometimes children act with each other in these circumstances for lots of reasons. Have they co-oped each other into creating a dynamic in the hope of bringing mum and dad back together. Or have the just developed a communicaton and attachment style that is conflictual. Sometimes it is too much activity, not enough good rest, wrong food types and they are tired from a school semester. More often than not its all of the above. But Pho you willingness to explore the issue is important, if it is only to bring you some peace.