You need to be sure that he has had all of the assessments he needs and that the reports are written in such a way that the CB is happy, and there is a documented history of disability. He also needs to have been actually using similar accommodations in school.
I've read that the CB is being less stringent with granting accommodations than they've been in the past, especially for kids who attend b&m schools, so what I've said here may be overkill. My experience has been as a homeschooler trying to get accommodations. It was a multiyear process to ensure that the history was there, and it cost quite a bit of money.
