U Mich Ann Arbor Full ride

Knowsstuff, I was wondering if your kids received the University of Michigan grant and if so did they get the same amount each year? We are also from Illinois, my son just saw his financial aid for freshman year at Michigan and he received a nice University of Michigan grant. My concern is for the future years because this first fafsa we have two kids in college but we won’t on the next fafsa and our income will also be somewhat higher. Michigan is only doable if he keeps that grant every year.