Don't blame hyesung for this he just need some space.
How long is it acceptable to refuse to as much as see your own child who's crying for you?
I think the difference is him not abandoning Byul, yes he did push them away but he's still there.
And if he does that for a prolonged period of time, he's inflicting that same trauma he went through to his own child. Even if he's physically present, if he's not truly there to pay attention to his child, it's pretty much the same thing.
Why are you blaming him? He was just traumatized by his own father and his mother left him, this is ALOT of stuff to deal with, what if he really spent time with byul but vented his frustration on his child? Wouldn't that also cause trauma for the byul? He needs space, don't you also need space when you're sad and dealing with a serious trauma? Yes he is an adult but that doesn't mean he can just go on without a break. He was just asking for a break, a moment to think about all this stuff that he's been through. And the things that he experienced, is just traumatising and depressing. How can he take all that in? He is not in the right state to show himself to byul at that moment. He was at a low point, how can you expect him to take care of Byul when he hasn't even solved his emotions yet?
I'm not blaming him, I'm saying that he needs to work through these issues to make sure he doesn't do the same thing to Byul his mom did to him. He already left once, for a long time, and now he's been hiding away for presumedly days if not weeks since they had time to track down his mom in this time. It's okay to take time to figure things out but when leaving your child behind and hiding away becomes a pattern like it has now, it's a clear indicator you need help cutting the cycle because this keeps happening.
He's doing the same thing his mom did to him by pushing Byul away. Trauma can absolutely be horrible and hard to deal with but as an adult, it's on YOU to cut the cycle and it's never an excuse to hurt other people, especially a child. I hope he can understand that and not push his family away, even if his mother turns out not to be a good person.