Irrespective of what the parents might claim, I believe they were well aware of the tenuousness of their child’s position at the school
Based on the evidence given by the school, the courts accepted that the permanent exclusion was a bolt from the blue for the parents. Given that the school had failed to go through any of the usual precursors to a permanent exclusion such as a temporary exclusion, I think the courts got this right.
in accepting a child with behaviour issues significant enough that they were unable to support
Again, from the evidence given by the school it is clear that they were able to support Bobby. They made the required provision then withdrew it for reasons that are unclear but which do not appear to have been related to Bobby's behaviour. If they had continued with the provision as they had initially it is likely that many of the incidents would not have occurred. Failure to take advice from the experts at the LA and CAMHS is appalling. And the clear evidence of victim blaming when Bobby was stabbed with a pencil and other pupils being treated more leniently (for example, the boys who attacked Bobby's sister and the older boy who hit other children with a stick and bit Bobby) is equally appalling.
This is not to justify Bobby's behaviour. It may be that he would have ended up being permanently excluded even if the school had done the things it should have. But it is equally possible that Bobby would have been involved in far fewer incidents if the school had simply continued with the provision they put in place initially then discontinued.