I think it’s a good idea to think about this question now. If I’d had to do it over again, I would have moved D16 back to the US while she was in high school. Applications and acceptances to a US university from a Canadian high school were very difficult.
I might have missed it, but is the student a dual US/Canadian citizen? If so, even if they finish high school in Michigan, they’d be eligible for financial aid from OSAP if they attend a Canadian university.
To be competitive for Canadian med schools, a student needs a GPA as close to 4.0 (on a 4.0 scale) as possible. My impression is that’s it’s a lot easier to get into a US med school. The competition to get into Canadian med schools is very fierce. There is no pre-med advising. Canadian students are on their own in that respect.