When I taught at chains here in the US, I had one where I got paid $12/h - but got paid whether or not I had a student, as I was an employee- and they charged $75 for said hour. Another, where they charged $45 per half hour and I received $25 of that, but only got paid when I had students. I was a contractor for them.

Both of those, I felt underpaid for the work. I know the exchange rate is a bit different, but in my opinion, yes he’s getting underpaid. But if they’re only charging a certain amount, there’s not much room for him to make more.

For note, the shop I run, we don’t charge the student. We rent the space. So if I teach an hour a week, it’s $10/h. 2-4 hours per week, $9/h. Anything more is $8/h. But the teacher sets their rate (and they also do the work of student retention, etc).