Responses
Well, it's pretty normal for parents to get the older child to help with their younger sibling, it's not so different from that. Besides, she only asked him to help while at kindergarten, since the mother herself can't be there with them... Don't be too hard on the mom, she clearly did something right if Yeonduk grew up to be such a great person.
id like to hear you defend why they dont explain it as they grew older.
forcing them became a habit. inexcusable.
forcing responsibility to a clueless child.