Sudden shift in her behaviour wasn't bcz she was changed or anything suddenly. It was due to fear of losing her son. There was a big communication gap between mother and son and it was also Pobmek's first time when he actually expressed his emotions before he left with Sun. When she heard about her son's accident...at that point she realised her ways can make her lose pobmek . She is very strict for her son bt it's not bcz she hates him bt she thinks what she is doing is the best for her son. She is an example of many typical Asian parents who think that what they are doing is best for their children and want their children to succeed or to be better than others. Bt they don't realise they themselves are making their kid's life miserable by constantly comparing and imposing their own selfish demands and thoughts.

I don't believe in sudden change too. But in this I would called it was the fear of losing his son. She was not listening to his son before because she thought she is doing the right thing. For Pobmek, he didn't talked about his feeling once because he thought she won't listen. I also think that she won't listen or change if it wasn't for the accident. We all can know that she love her son and want the best for her son even though what she did were wrong. The guitar scene actually the worst but to be honest, that was reality. Most of Asian parents don't think art(especially music) as a reliable career. And all she want was a reliable job for her son future. The thing that hit me most is when Pobmek said "Mom is kind to anyone except her own son".