Never mind that - she’s in and out of her classroom and taking time off at the drop of a hat! In all seriousness I’m sure it would, in real life, be considered a massive concern and he would be moved between classes.
I've just binge watched the first series. To summarise without spoilers, a Teacher makes an accusation of rape against the parent of a child in her class. The child remains in the class and the teacher at work throughout the investigation.
I'm sure this wouldn't happen in reality, but the teacher did nothing wrong, so why would she be moved? Likewise the child did nothing wrong. How do you think this would be handled?