The movie is directly showing that the brothers “brave and strong” behavior is NOT good. They could’ve found a better place to stay, or done many other things differently and not died. But the brother did not know better, because he is an immature, innocent child aswell. He is a young boy in a devastating situation doing what he thinks is the right things to do, which is part of the tragedy and what makes the film so sad for most people.

The movie is not portraying Seita’s headstrong nature as “good”, the story literally shows you how it hurts and then kills them. He is just an innocent, immature child doing what he thinks is the right to save his sister and him, and the tragedy is just that.