My brother is 18 yrs. old he and his girlfriend who is also 18 just had a baby girl. The Father of the girl has paid for everything out of his pocket because he has no insurance that would cover the baby and his daughter. They currently live with her parents and are now wanting to move to San Antonio. Her father doesn't acknowledge my brother and he is to stay in one area of the house while he is there. He is also telling him that he is taking the baby to San Antonio and that if my brother wants to she his daughter then he is to pay him rent while living there and go to school, which is reasonable. However my brother doesn't want to go, he would rather they stay here and live with our parents. Her father is pretty much running the show and the girl does everything she'd told because her father say she gets money from social security every month and if she doesn't go then she'll no longer receive her money and disown her. Can she leave with the baby if my brother doesn't agree. There not married but the baby does have his last name.