Ncrow probably won't do that. Akane's mother was most definitely at least in a relation once, judging by the fact that akane was born and Ncrow specifically states on the game page "As long as I am alive, there will NEVER be NTR". If she's still got a partner, then it will never happen.
It's also just morally unjust towards akane to do it with her mother, so that's another reason. It's kind of the same with mayu's mother.
