In this case, the mother is insisting the daughter is a "Christian", but the mother isn't the only person who gets to decide how to raise the child. If this mother didn't want her daughter to be raised with an atheistic influence, she should've chosen another man to father her child! What you say is true. This mom will have her hands full, but the sire does have a right to be part of the decisions. He sounds very unstable though and is willing to use his daughter for his own ends. I'm sure this Mom has wished many times that she had found a better father for her child. However, I'm sure that that was not foremost on her mind at the time.
Oops... I replied too quickly. You have now read the other post. I need to wrench myself away from the computer now...