Maybe the law is different in Pennsylvania, but in New York's courts, this case would have almost no chance of survival. And here's why:
As noted in "How to Prove Your School Negligence Case Under New York Law," New York's schools will not be held accountable for the injuries sustained by either a student or a third party (such as a parent) if the injuries were sustained as the direct result of a spontaneous, or unforeseeable act. Stated differently, unless the plaintiff can prove that the school either knew or should have known about an imminent danger on its premises - and during school hours - yet failed to act reasonably to prevent it from occurring, the plaintiff will lose.
I, for one, can't see how the plaintiff in this particular case would - or could - prove that.