I hope the health days help your son and I think that approach makes a great deal of sense. One thing you might consider if you're looking to accelerate him using the Iowa Acceleration Scale is that there is a section for attendance at school. A history of excessive unexcused absences and tardiness or even frequent excused absences would give him a lower score. Obviously your son's health comes first, but it may be a factor in getting him in a better situation.