No, because I get that you mean people should be given second chances. But it doesn't mean it should be done just as easy as that. Because that's years of trauma and pain, you know? The only person who's allowed to forgive Hyesung's mother is Hyesung himself—because he's the one that suffered the most.
Forgiveness shouldn't easily be used when people are hurt in such an extent. I too, forgive my parents when they hurt me a lot. But our fights literally just last for weeks or a month. Not years. There's a heavy weight on how long time passes by because it measures how long your heart's been carrying that burden.
If Hyesung's mother really did want to be part of HER SON'S FAMILY, then she should've apologized to him. Not just barged into their life. That's the most sickening and shameless thing someone like her could do. She doesn't have the right to leave her son and suddenly go "Hey, so I sweet talked your son and now he likes me more than you—his own mother—instead of actually apologizing to you years that ago"
But of course, Hyesung is the same to some extent. But he actually committed to his responsibility and loved Byul as his family and son. He didn't leave him. And that speaks volume for itself.
Some people can regret the terrible decisions they have made and try to be better even if it’s years down the line and I think that’s the point. The grandma knows she f’d up but wants to be apart of the family without bothering Hyesung. Hyesung has a right to be upset and so does Byul because he really was abandoned too but chose not to hold it over Hyesung’s head. This isn’t a black or white situation. It’s extremely complicated and sad.