2nd Prince ends up having to kill himself, but according to the subordinate who was there when he drank the poison, the way he acted at his end was befitting of a leader. He only learned how to be humble to late into it.
1st Prince ends up losing his title and being handed over to Liam. Liam forces him to live as a commoner on one of his colonial planets. Where, surprisingly, he enjoys it and finds a better life for himself. Also, all his wives divorce him and leave with their kids, except 1 since she was a commoner to begin with so she was ready to accept death. In the end, he really does enjoy his life.