Apparently, her little brother doesn't care if his older sister is one of the biggest names in Korean entertainment, because he's más bent on ignoring her. iu uploaded screenshots of her conversation with her little brother onto her fancafe, and most of the chat is iu trying to get her brother's attention por texting "Hey" over and over again.
At one point, iu gives up with the string of "Hey"s and says instead, "If tu keep ignoring me, I'm going to stop giving tu all allowances." Only then he answered, "Why?".
After a few 'conversations', she finally concluded. "Oh, I guess tu just don't read my texts anymore."
The conversation amused many fans, who commented, "In the end, they're just normal siblings..", "To him she's just the annoying older sister", and "She's looking out for you!"
source: allkpop