Let me read between the lines here:
1. He is transferring and will be required to sit out the fall 2019 football season, assuming rules are followed (2019-2020 school year).
2. He "withdrew" from Curley this spring 2018 (2017-2018 school year).
He will be repeating his current grade since he withdrew, so even though he is sitting out next year of football, he won't be losing a year of eligibility because he is repeating the grade he never finished.
Sound about right?
Sounds to me like the key to beating the "transfer must sit out a year MIAA rule" is to withdraw and not complete your current grade.