He has a great relationship with the athletic director. If we can demonstrate that there was any assignment that he should have been allowed to make up but that he wasn't, that alone is probably enough to raise his grade.
And if we suggest that perhaps she wasn't aware that a particular absence should have been excused, that is an easier position for the teacher to accept than us trying to convince an assistant principal or department head that the entire year the teacher failed to enter in assignments on time (or at all), repeatedly doesn't have time for her students and generally is a disaster.