Responses

He is an adult now "mentioned here". (●'◡'●)ノ http://www.mangago.zone/read-manga/bl_motel/uu/ibx_chapter-58/pg-17/

No he is 19 you can check it here
https://toonkor.show/BL%EB%AA%A8%ED%85%94_1%EB%B6%80_%ED%9B%84%EA%B8%B0.html
How old was the lil brother again