In the story of the manga,
it is said that after Ei Sei escaped Zhao (and eventually rescued by Qin troops), the King became aware of his escape minutes right after they exited the last gate, sending Zhao's cavalry to search for him. Everyone but Sei died, and even then had to be rescued almost at the end of the way.
If they went through all this trouble to just get Ei Sei, it is only strongly implied that Sei's mother, who hadn't been rescued, would be in grave danger, probably geting killed some time soon (since Sei's Zhao pursuers at some point mentioned that it didn't matter if they captured Sei dead or alive), and if not heavily watched and/or tortured and disgraced more harshly that she had been before (since people's logic of those times was so flawed that they would go so far as to blame some innocent person from a nation for the crimes of some other person from the same nation).
Having said that, I am wondering how the hell did she get out from Zhao? (seeing as Sei's initially unnoticed escape was barely possible.)
But having read until chapter 185, yet another question arises in my head.
If Sei and his mother hated each other so much (she tried to kill him), why on earth was she rescued in the first place to begin with? A thorough explanation on this would be great and would stop me from having to open a new question.
Aside from this, comes a question that might be considered off-topic, but I'll ask it anyway just in case. Is there any similar real life historic records chronicling how Lady Zhao somehow moved from Zhao to Qin?
I've done a quick read of Wikipedia and seem to not find anything, however I will keep on researching and update this if I find the answer on my own.