Responses
Dage means eldest brother and gege is big brother, u can use both of them to anyone who's closer to u, whether it's blood relationship or not... I'm not sure about formal but u can use it everywhere be it jokingly calling friends like that or actually addressing it to smn? In this case Xie ling was calling his eldest brother Dage and han Siwei Gege. I hope u got me, I'm still learning so..
Thanks a lot, Hualian Worshipper, for picking this up. Your translation's good and easy to understand. And this chapter was so fun, I love how Xie Fengtong had a one-sided beef with Siwei while the latter wasn't even present btw, is 'dage' more formal than 'gege' in terms of usage?