Responses
Well in korean the term 'hyung' can either be used to refer to your blood related elderly brother or it is commonly also used to refer to elder males to whom you are quite close. It's a term only used by males to refer to other elder males. It doesn't matter if they are blood related or not. Similar term for females would be 'oppa' and similar term to refer to elder females is 'nuna' by males and 'unnie' by females.
Is it just me or do Koreans use the term "hyung" too loosely? ╮(⊙_ʖ⊙)╭
Like are they brothers? (Hopefully not, I cannot deal with incest) Are they colleagues or friends but with a slight age gap?