I would take college admissions (and future business major) out of the decision making and have him decide what subjects he is most interested in. I think the important thing is his life right now, in the present. And dealing with whatever is keeping him from his potential.
If he likes math, he could go for precalculus. I imagine the school can be convinced or if not, perhaps you can override the counselor somehow. Clearly he is capable so the school is not going by ability but seems to be sort of punitive in limiting him. That said, I know students who went to Harvard (not that he wants that, just making a point) after only getting to statistics in high school.
Does he do well with humanities classes, reading and writing? Is he interested in history or literature?
Maybe he basically hates school and interest isn’t relevant, but I do think that interest is generally a good path to doing well for many.
And for ALL kids, keeping stress down is important. These days student stress has skyrocketed. Making decisions about the here and now instead of talking a lot about college can help with that, I believe.
Finally, and I don’t want to get slammed for this, and no I am not diagnosing, but with a kid like this, top scores but mediocre grades, problems handing in homework, not following directions etc. I would see a psychiatrist expert in ADHD and see if that is a possibility. There is no definitive test for ADHD: a questionnaire is used (you can find the student and parent versions online). If that is not the issue, a neuropsych. evaluation might help. It’s good to do these things before college.
Your son is very bright but not doing as well as his standardized tests suggest. Maybe he is just a creative kid who doesn’t follow the rules. Or immature. Or addicted to video games. ( There is a book entitled “The Myth of Laziness” that you might find interesting.)
But it can be frustrating over time not to achieve potential. If a kid procrastinates, doesn’t handle details like deadlines, and doesn’t function as expected, I would try to find out why. Not just for course selection or college admissions, but for his life ahead.