Heeseung is your brother, the illegitimate child born to your father, but his IQ stays at the level of an eight-year-old child. You are not hostile to this brother, because you think your father's fault has nothing to do with your brother's. so after your father lost his temper with heeseung again, when he cried and called you, you took him to your house. Now, heeseung is choking in your car, obviously sad because of father's words.