There is an interesting parallel between Ramayan and Mahabharat, when it comes to the fate of these two sets of brothers. Two brothers when faced with a similar situation took similar decisions and met the same fate as a result of that.

In Ramayan Ravan's brother Kumbhakarna was not in favour of war against Shri Ram. He advised his brother to return Sita Mata to Shriram and not escalate the hostilities with Shriram. However Ravan did not listen to his advice and his stubbornness resulted into a massive war at the shores of Lanka. When it came to choosing sides on the battlefield, he picked the side of his brother and perished. Same was the case with Duryodhan's brother Vikarna. Apart from Vidura, Vikarna was the only person who spoke against the mistreatment of Draupadi and tried to stop it. When it came to war, he knew that his brothers were on the side of Adharma. Despite knowing that he chose to fight alongside his brothers and was killed by Bhima in battle. Vikarna was the only Kaurava brother whose death made Bhima sad. 

On the other hand, there was Vibhishan, another brother of Ravan. He also knew his brother was wrong and advised him to do the right thing. When he knew his brother is beyond reason and is hellbent on staying on the side of Adharma, he picked side with Dharma on the battlefield and joined hands with Shriram. He survived the great war and it was because of him whatever was left of Lanka survived. He was made the king of Lanka by Shriram and he brought peace to the Rakshasa kingdom. Similar was the case with Yuyutsu in Mahabharat, who was Duryodhan's half brother. Yuyutsu was the son of Dhritarashtra through one of Gandhari's maids. He never approved of his brother's actions and was always sympathetic towards Pandava. As a kid he informed Yudhishthira about Duryodhan's plot to poison Bhima. When the war became inevitable and both the armies came face to face on the battlefield of Kurukshetra, Yudhishthira made an appeal to everyone in the Kaurava army to choose the right side. At this point one lone chariot crossed over from Kaurava side to Pandavas. This lone chariot was of Yuyutsu. Yuyutsu survived the war and after the war he was made incharge of taking care of his father Dhritarashtra. When Yudhishthira decided to appoint Parikshita as king and depart to heaven, Yuyutsu was chosen as the guardian to the throne. A role similar to what Bhishma Pitamah played earlier. 

The irony these days is that many people glorify the actions of Kumbhakarna and Vikarna while seeing Vibhishana and Yuyutsu in a negative light. We even refer to Vibhishana as "Ghar Ka Bhedi". We believe that by mentioning similar accounts not only once but twice our ancestors wanted to tell us to be like Vibhishana and Yuyutsu, if ever put in a situation where one has to choose between Dharma and Adharma. Shrikrishna himself killed many of his relatives like uncle Kamsa, cousins Shishupal and Dantavakra, step brother Poundraka etc because for him upholding the Dharma was supreme.