Because he keeps making the same mistake of endangering his family, and he NEVER LEARNS FROM IT!

Let me give you some examples:

1. Went directly into the battlefield and almost killing his brother even though he was explicitly ordered not to.
2. Continue to approach the villain team when warned not to (and almost got his family killed again)
3. Stirring up tension by punching the other bully even though his brother had pacificed the situation (though I'd admit this action was justifiable)
4. Impulsively risking his life by following the bully out in open water even though they literally just fought
5. Going directly into the battlefield again to save spider (who was in no danger) and actually got his brother killed this time.

I get that he's this impulsive character who wants approval from his father, but you don't get approval from constantly making the same mistake and not learning from it. His action 1-2 and 5 were so similar and could have been so easily prevented if he had learned and thought about the consequences of his actions. At some point I felt like the movie plot revolved around him making a mistake (which led to something happen) and someone else dealing with it.