What did the mum do again? Abandon him?

Yep for years and ahowing up just to blame hyesung

Thank you

Hye's dad was abusive and she couldn't take it anymore, so she left, leaving Hye alone with an abusive father.
Then, when Hye's pics showed up in the media bcs of Dojin, she went to meet him and then blamed Hye for not searching for her (cope of the century).
So yeah, she abandoned her child, left it with an abuser and then blamed the child for not trying to find her.
She also started a new family and had more kids ...