Because the father ended up with money issues. Thanks to her probably being greedy she left... And all of a sudden because he's in a wealthy family they all popping up. Nah they both are trash..
Hye's mother was abused badly. Hye's fathermade her into a punching bag and took all his frustration and anger out on her. She was probably also blamed for giving birth to a weak looking alpha i.e. Hyesung. She could have left Hye behind because either she too ended up resenting Hye for being one of the reasons for her abuse or that she was an omega and could possibly won't be able to take care of him. Anyhow, you can't overlook the fact that she left a defenceless child with an abusive father.
listen when i say forgiveness i mean it so that Hyesung can move forward in life and you can forgive someone and still keep them away from you, forgiveness is so you can heal and move forward. He doesn't have to accept them or even talk to them. Forgiveness is a very subtle yet effective slap
Guys i understand that the parents are wrong for neglecting Hyesung and that he shouldn't accept them, the dad is an asshole and i hate him, but i genuinely want to hear his mom's reasons for leaving and why she couldn't even take her child with her because the condition of the house was bad. Hyesung forgiving them and moving on is the best thing for him im not saying accept them back into your life but just stop letting them affect yours so much