My new novel Alien Day is all about sibling rivalries, both human and alien. I write about Alien Day and Alien Morning (the first book in the series) in this post for the Tor/Forge blog, and then I mention some other classic science-fiction sibling stories and bring you up to date with some newer novels, too. Take a look. https://www.torforgeblog.com/2021/05/22/some-must-read-sibling-rivalries-in-sff/