Responses
Spoilers..
If i remember in the novel grannybitch is the only one against in their relationship, so yoontae's family is ok and the dad only wants to see grandkids before he dies(he literally says or say i quote he wanted to see his grandkids before going into the coffin) though after jeongseo met yoontae's good for nothing granny, she was never mentioned again

So, I think we all hate the old hag grandma that basically abused Yoontae when he was small. But I'm starting to dislike his sister too. Seems like she was too spoiled by yee old granny as she's stirring up shit on purpose mentioning visiting grandmother and such. Sure, she could have daddy issues, but that's not her brother's fault... I'm honestly surprised, Yoonate's reaction was more meek than mine would be...