Wrong approach. It’s not a Constitutional issue, it is a fraud issue. The school system purports and promotes itself as a provider of education, which pretty much includes reading, writing and arithmetic. Failure to do so is fraud. And that is a viable legal approach.
Those children need better representation and should contact Jay Sekulow’s organization: https://aclj.org/
So, the truth of the matter is that they need lawyers who understand RICO Law, not the Constitution.