Can you get a hold of the text book? Old class tests from previous years? Do you have a friend who's child took this class last year? Is there an end-of-year test that DS could take?
Basically LOG exists. It can't be wished away. What percentage of the students get placed in the Advanced Math at your school? How closely does your school population resemble an average American cross section? That should tell you how reasonable the teacher is being.
For some reason, I tend to believe teachers when they say that they are in touch with what their average students need. It's wonderful that the teacher recognized that your son is bored - that's unusual.
Best Wishes,
Grinity
