What a hard time for all of you, so sorry. It sounds like your son sure knows what he needs to in order to pass this test. I bet there's a way someone in charge of the tests can arrange a special day/time to read the test to your son if allowed.
No need probably to tell you to give your son praise for all his effort in trying as I am sure you've already done so.
I am keeping my fingers crossed for Friday's test passing.