Regarding Tong Tong’s mom being a ‘whore’ (as that one comment put so eloquently):
If you read chapter 4 again it literally said her mom put off dating until Tong Tong was close to finishing primary school. It just turns out that the dude she’s dating, most likely long term since it’s suggested that he even moved in with them, is a fucking pedo. How was she even suppose to know he was a creep?? After that she had a couple different partners but never brought them home because she was worried of said previous situation happening again.
In terms of being a responsible parent:
Yes I agree to a certain extent that Luxi’s mom is more ‘responsible’, worrying about her daughter’s grades, cooking her dinner, telling her to sleep and working herself to the bone to support the two of them, but you can also see that she is overbearing with the amount of pressure she puts on her daughter. She’s very much the strict Asian parent stereotype and you can see how uncomfortable Luxi is around her to the point she can’t even smile without being questioned. This type of ‘responsible’ (read as controlling) parenting style usually ends up with the child just hiding everything, developing a complex of ‘I’m not good enough even though my [parent] is doing everything they can for me’ and eventually distancing themselves from said parent once they’re an adult. Meanwhile Tong Tong tells her mom all her problems and not only does her mom listen to her, she also tries to help as best she can.