raws went from 0 to 100 real quick (╯°Д °)╯╧╧ that guy needs to be disposed off

I think we're not given the whole story here. It seems the mom left them because she had somebody else. They are trash parents, Idk get why he is looking for his son and wants to see his grandson too

Yeah, they're stupid parents.
But as I've said we weren't given the whole story. In the new chapter, the dad is claiming that his mom left them voluntarily. And he was shocked when he realized that HyeSung blamed him for that. There's just something amiss here