I haven't seen the film, but I have taught many deaf children, and I don't recognise the comments in this thread.
Deaf children have support and sign language translaters in schools when they need it. Some mange with hearing aids, some don't. All get support and monitoring.
Signing is common in main stream school, I learnt some subject specific vocab when I realised the signers in my sixth form classes didn't understand the science well enough to sign it.
Many deaf students have two or three LSAs in one lesson, two to take turns translating in sign, one to write notes,
They are very well supported indeed.
Deaf students are no where near as isolated as children who can't speak English, as can interact with the teacher and other students in writing, and most can write very fast! so even on occasions when there has bee no translator, (strikes, etc) they can still take full part in the lesson, at secondary level, we just make sure all information is written.