Yall r forgetting that byul is still a kid, a teenager at that, and he just wanted to know his grandma, idk why yall are shitting on him like that. And for dad, I don't think he was in contact with her at all, I guess he wanted to know about her. It's obvious hyesug still has some type of feeling for his mom that he hasn't heeled from, no matter how awful she is, it's still his mom