If that's the case, she should tell her father and ask him to make arrangements to go to Family Court and ask for a change of custody. It may also be done voluntarily if the mother will go along with it.
Usually the court will begin to listen to a child when they turn 14-15 years of age and appear to know what they really want.
The court will look at the best interests of the child and determine a change of custody if the parents cannot agree. While the court may listen to her wishes, the court will not rubber stamp your niece's desire to live with her father. She will need to articulate clear reasons for the change.. The fact that her father buys her more things or does not set a curfew will not help.
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