Post #7 college choice is irrelevant- the OP is considering Michigan or a much less prestigious school while post #7 is comparing the same general tier.
The key is future goals. Plus- although he gets no money from Michigan if he is a top student who will be in top classes he likely would benefit from the courses available at U of M. Think in terms of honors classes, numbers in majors and peer group. Will he be better prepared for work/grad school? Will he find his academic peer group at both places? For math and related subjects the possibilities for grad level courses should be better at U of M. For business majors (accounting, actuary science) he needs to be sure he can get into the business school.
With instate tuition his debt load may not be as high as if comparing OOS/private schools. Aim high for the best academics. Decades later he will not have regretted giving up the better school- he should have been able to pay off loans with such practical majors.