You also have to kinda understand the context ? Her brother has been ghosting her and the rest of their family for probably weeks/months or whatever. She got the chance to go to South Korea ( because if I’m not wrong they’re not living in S.K currently and Jihoo is only there temporarily ) so she decided to go visit her brother that has been giving no sign of life for who knows how long. I’d say it’s not that bad, it’s just a family member who wants to see him after he’s been ghosting them for a long time ( especially when they don’t seem to be on bad terms or anything )
I understand the context and it still feels like an overkill to me.
That sister of his is hella weird. She acts like a stalker. I have a younger brother myself and I cannot imagine acting like that. I would first probably die of shame, second I just wouldn't feel the need to track him down like some crazy ex-girlfriend. Dunno....it just feels sooooo unnatural and forced.