You don’t need school if you don’t need a degree for your job.
Learning is my all time hands-down favorite hobby. If you put in the work you can learn all the things you learn in a CS degree on your own and in a much shorter time.
The problem is getting good text books since they’re expensive (when I was in school you couldnt google everything).
I realized I could social engineer my way to free books by appropriating college letterhead, pretending to be a professor, and writing to publishers asking for evaluation copies of books I wanted to read.
Most students dont come to CS already knowing everything that is taught - that holds true regardless of how easy the school is. Many students decide they want to do CS only later on and even if they hobby coded, they did not learned everything yet. I code professionally for years and still dont know everything nor everything that is currently taught at universities.
Either he had very easy school or picked courses he already knew about or he splits what he learned into "important" (the ones he knew) and unimportant (new stuff).
It's really not that unlikely. I had the same experience, I've been doing a lot of hobby programming before uni. Most of what we learned I was already quite familiar with from either experience or reading books. Pretty much all of DS&A but also more theoretical things like the halting problem.
Whether the degree was worth your time and money, and whether it was interesting, is an entirely separate question, of course.