I think doule parents swap the babies when taoxi's bio father came to take him , from my understanding when both taoxi mother and doule mother were pregnant at the same time and toaxi mother was far away from her home in small village where she spent her pregnancy and died at child birth and when her husband found out and came to take his son doule bio family swapped the babies for better life for doule because he was weak and sick from birth
Cause if they like wanted to exchange babies or whatever I think taoxi bio parents are rich or if not rich then they are at least capable of caring for two child but problem lies with people greed and if both party agreed to exchanged babies than why would taoxi parents treat him so horrible like one would treat their savior child better and taoxi I might be wrong but that's my understanding if I'm wrong then novel people correct (▰˘◡˘▰)
What @Hualian said is true after taoxi's birth father came to get his son after hearing the news about his wife's death, the doule family swapped both families sons and lied to taoxi's birth father. They didnt say to his father (taoxi's birth dad) that his wife gave 2 kids maybe cause his wife must have done a sonogram or something before to know that it a single child. They doule family treats taoxi badly due to the fact that the miss their real son who is of their blood and maybe whenever they see taoxi they realise their son is away and be ashamed of their deeds and convert that as a hate towards taoxi.
Taoxi's birth father doesn't know that doule isn't his actual son at all.
Taoxi's parents never gave up their kid. The whole family treat the swapped kid as their own flesh and blood & never knew their real one is suffering from abuse all his life. Even the mother of Lin Qinhe, the closest friend of Taoxi's mother, didn't knew about it. And treated that kid better & neglect her own son's feelings. Never knowing her best friend real kid is out there, she would have saved Taoxi if she knew.
Even Duole's real father didn't knew, until he find out about the birth mark after few years passed. And changed from a doting father to being cold towards Taoxi, because he isn't his flesh & blood. Everything started with the greed & selfishness of Duole's mother.
Like I totally understand duole's parents giving him away. They were poor and he was sick. They wanted him to be able to live a long fulfilling life with people who could give him that. But why the fuck would Taoxi's parents give him away??? No matter what the manhua says to explain, it makes no sense to give your child to individuals in a worse situation than you are?? They're horrible parents.