I am not a teacher.
My immediate answer would have been, 'has been given'.
Without context any of them could work, although I feel that 'will be given' is the least natural choice. How do we know what decision the school will make? It makes more sense to me to assume that the decision to give him one more chance has already been made, so I would use a past tense. Of course, the decision and him being informed of it are two different things that may not take place simultaneously, but the past still sounds more logical.