I think Byul is going to crash at Siwoo's house during the heavy storm is now approaching

I think Siwoon's and hyesung's parents aren't that much different from each other. I hope Siwoon does not take Byul's side.

Byul is a kid and doesn’t know the full story. He just sees a sweet very old lady being abandoned by her family. I think his parents should have talked with him since the beginning and explained why they cut ties with her.
Seeing an elderly person suffering, it is normal to empathize with them, it is even human.
I didn’t read the prequel but by the comments I understood what happened. Parents should tell their kids instead of just ignoring the issue. Of course it was normal for Byul being curious.