@Kamelpov "school is harder than other country" That's a very broad statement, and it definitely doesn't always hold true, but that's not really the point.
"he has the potential to go further" At what cost? I could say that's true for literally everyone in the world, that they have the potential to go farther with a college education than without. However, he is living at someone else's house and only begrudgingly. His current guardian, his aunt, only took him and Suzu in after they had been rejected by everyone else, and based on what she has actually said to his face, she is not too keen on letting them stay.
Maybe she actually thinks differently, but she hasn't said that to him.
Given that, it is a perfectly normal decision to seek stability even at the cost of potentially greater achievement. That's a decision that a lot of people very reasonably make because it is only potential, not guaranteed.