@Jb9090 I have a theory about these two. Maybe they can`t take their own lives but as the brother said, if someone from the clan has a child with a normal human, they kill that person. So, I`m thinking the only way that the mother thought she could die was getting a child.
And estrelle didn`t die because there is someone that remembers her. The spirit friend (and the animals, but I don`t think they count).