Hizashi never hated his brother.
He detested him, he loathed the system that had marked his forehead, forever separating them, but he did not hate his brother for the burden that he had to carry.
He hated the fact that he wasn't allowed to carry the burden for him.
He saw the way the elders crushed out any semblance of personality, any fraction of rebellion, of will to fight for what he believed in was cast into the darkness under direct tutorship of their father. Their whispered words of how they were going to change the clan turned into his brother turning away from him.
His actions, once a symbol of his devotion to his brother, now seen as just the actions of a loyal branch member.
Years passed after he received his headband and his rank of genin, and the brothers hadn't spoken after his aniki hadn't said anything when he sat at dinner that night. Their words had faded into the words of a main and a branch member.
He believed in fate, like his son would after his death. He became angry with not only the clan, but with his brother as well. The brother that had turned his back to him and their dreams, which had become a mere puppet for the elders to do with what they will.
Angry enough to send out a wave of killing intent, which changed his sons mind in the worst ways.
But he when he found out Hiashi was going to die, things changed.
He had narrowed his eyes when he first heard of it, an hour before he was called in to a private meeting with his father. His friend had told him to screw the family, but he couldn't.
For all their problems, for all the years of separation, he would not let his brother be killed.
The moments before his death he realized how he had never fought for anything. How he, like his brother, had fallen into the trap that was their family.
He had blamed his brother, but he was just as much at fault.
So he made his choice, and died by it.
In the end he still hated the Main House, but that was his choice, and he still loved his brother