While you and I would not want this kid in MY kid’s school, EVERY court in the nation would shrug and say; “Too bad”.
A free public education is a free public education.
Apparently one court agreed with the school and rescinded the order requiring them to take him. That may have been because the troubled kid’s parents didn’t fight it but at least there was some recognition of the rights of everybody else not to have to live in fear.
To your point I bet if the troubled kid’s parents sue they will be able to force the school district to pay for private tutors.