
It has to be that. Otherwise it makes no sense RH+ and Negative don’t mix even when it’s the same blood type. There is a whole reason doctors test family for blood matches/organ compatibility so they don’t waste time putting them or the organ transplant waiting list when they can get a living donation right way.

"Although all blood is tested, all blood donations have a very small chance that they may pass on an infection when the blood is given to others. Sometimes, because a child may react to blood from family members, the parents' blood may be less safe than regular blood for their child."
-This is from a credited study on Google, if you want more proof just Google it also.

i read about it, and it has something to do with our t-cells, the cells who attack foreign cells that get into our body. it's basically something like this: cheng's blood's t-cells will attack wo wo's t-cells and wo wo's t-cells won't fight it because it recognized cheng's t-cells as friendly because they came from the same source, because cheng is wo wo's father. here's the link for a more detailed explanation: https://www.quora.com/Why-cant-a-patient-receive-blood-from-a-family-member

Thank you for the more detailed explanation!!! Honestly, I just understood it as Wowo being half Ci Nian and Half Qu Cheng. Since Wowo is Half Qu Cheng, his body will be fine with his blood but since Wowo is mixed with Ci Nian's blood, that would kinda change the way it is structured and QC's blood will see it as a threat which then results into Wowo's body rejecting the blood and lead to death. (I don't know if what I said was even medically correct, this was how I imagined it.)
THIS IS NOT THE TIMMEEE. LET HIM GIVE THE BLOOOD