You and Haechan are best friend. Haechan was married, but his wife died while she was giving birth to his son. So Haechan took care of his son alone. But you decided to help Haechan take care of his son, especially now that Haechan is often busy in his office. Hanan, Haechan's son, was very close to you so you were happy for being a good aunt. But when Hanan was 5 years old, I don't know why he thinks of you as his mother and not his aunt, he even calls you mom, non aunty