Are there no other foreign languages at all? Maybe he could take 2 years of another language?
If he has any ideas about colleges he’s interested in another thing you could do is reach out to an admissions counselor at the university.
My D22 had a schedule conflict at her very small high school and couldn’t take Chemistry. When we went on a college tour the summer before junior year (or maybe 10th grade) we asked the Admissions folks and they said it was okay for their college.
It can be different for different colleges though.