“I don’t think avoid foreign language is an option for OP’s son and those are the kinds of classes that could be challenging.“
He’s doing Latin as his foreign language which is actually his favorite class (mostly due to the teacher, as well as the logical structure). So that’s not a problem, he can have the same teacher all four years (up to AP Latin if desired).
We met the teachers this week and both his math and English teachers are strongly recommending he does the advanced courses because otherwise he’ll be bored. He seems more willing to take the advice from them than us, mostly due to a severe lack of self-confidence. So it looks like his classes for next year should now be reasonably straightforward to decide.
But convincing him that he is good enough to do well will take some time, he feels somewhat intimidated by the success of his older siblings, who found school much easier and always got As. The key may well be in getting the right teachers who can understand him and provide encouragement.