aight so the thing about korean grammar is that you refer to members of your family (your mom, your dad, your siblings, your dog, your house) with 우리 (uri), which means we/our. so basically it’s like communism. if you’re joy hong you would call jay 우리 오빠 (uri oppa) with the english translation ‘my older brother’ and the literal translation ‘our older brother’.
it’s the same for husband/wife, you would call ur husband 우리 남편 (uri nampyeon) and your wife 우리 아내 (uri anae), it’s like this bc you share them with your family? so basically yeah communism if you catch my drift. jay is joy’s oppa but he’s also steve hong’s son and kitae’s little brother. he’s part of the family whether you want it or not
this is not the case with boyfriends/girlfriends, because you call them 제 남자 / 여자 친구 (je namja / yeoja chingu), which translates to MY boy/girlfriend. yes. you do not share your bf/gf with your family bc they ain’t a part of it yet. jay has definitely accidentally mentioned daniel to joy at least once as “제 형석이” (my hyungseokie) and joy’s been like oh, he’s YOUR hyungseokie huh.
meanwhile daniel has accepted jay as part of his family (they celebrate chuseok together?? and chuseok is for your family?? i said this on twt already but daniel and jay deliberately spending chuseok together suggests that they consider each other family one way or another, hence on top of jay calling daniel “my hyungseok” i raise you this:
daniel calling jay “우리 재열이”. OUR jaeyeolie. like they’re family.