Who decides what makes a good mother? Do the courts decide or does society decide who makes a good mother?

Answer 1

I don't think either one of them do.
I think the person decides (based on their ability) if they are going to be a good mother. Society helps to define what is considered to be a good mother and if the person is unable to do so, it is the courts then that make the decision. Good mother or bad mother.
Not everyone is meant to be a mother. In a case like that they shouldn't be.