So Sh’mu’el told him every word and hid nothing. ‘Eli replied, “It is The LORD; let him do what seems good to him.”
Sometimes our nature cuts both ways. The very qualities that give us our strengths reveal our weaknesses. When Eli hears from Samuel that The LORD will attack and destroy his family he doesn’t fight it. When he heard what his sons were doing, he said nothing to stop them. That is why divine punishment is being brought down on his sons and their sons. Eli submitted to the will of the Almighty regarding the punishment. He could have cried and begged for forgiveness, but he just accepted it. Some would argue that is humble, good and reasonable considering the context. Avraham argued with the Most High, as did Moshe when He was ready to mete out punishments. It is easy to say they are more righteous than Eli. Perhaps he should have fought for his grandchildren, even if he had let their fathers corrupt themselves.