how can my daughter leave new jersey with our grand baby that lives with her and her boyfreind /father/ to come back home?

The child was born here in Utah and after appovimently one year old her boyfriend talked her into moving by his family in new jersery. he was verbally and physically abusive while here before they moved but my daughter never reported it to police only to us and a few friends. she moved up there and it still happened but here self esteem and judgment were tore up and she attempted suicide. after getting out of hospital he got verbally abusive and used her "mental Ilness" against her and said that if she ever left him he will get full custody and she will never see the child because of her "mental" illness.. he leaves her with the child for longer periods than he says he would so that he can go over to other womens place and she cant rely on his deadline so she is now in trouble at work constantly. they got in a yelling match a few weeks ago and she lost it and physically attacked him with her hands. He went directly to the poklice and filed a report. She just wants to leave and come bac