If it was the general studies high school "biology" he didn't have, he didn't really miss anything. it's all common sense garbage anyone with half a brain knows already. One of my kids needed to do the whole course in a month to graduate on time. So she took it after school at the adult education center. She completed the entire course in a week, 4 days actually, with not a single mistake on the exams.
Pathetic what they call "general studies" high school biology these days.
It was biology for biology majors and pre-med students.