Responses
followng
1. http://www.mangago.zone/read-manga/gosan_no_heart/
2. http://www.mangago.zone/read-manga/owaranai_fukou_ni_tsuite_no_hanashi/
First one is the story about the younger brother and the second one is a spin-off about the older one.
Stories where brothers get into relationships (with other people, no incest pls)