Bruh, I don't care if the kid is nonverbal. You don't let kids scream for two hours, let alone one. I get that teaching is hard, but you need to be figuring out what's happening, FFS.
Even nonverbal kids can still communicate, and it's the teachers' faults for not at least calling the parents sooner at a minimum.
I would rather the school interrupt my work day multiple times to potentially help them with something minor, rather than wait two hours for what turns out to be a medical emergency.