Is there a way she can be emancipated or have her custody signed off as she can’t stay with her father due to a court order?

My fiancé currently just turned 17 while I am 18. She's been staying with me for about 10 months and living full time for about 2. Her parents have been split up for years on good terms but her mother has full custody. Now although she has full custody, she has not been under her care for over 3 years because she was tired of switching schools she started living at her grandma's house. In the last year, her grandma has kicked her out and because she didn't want to go to her mom’s house. She went to her dad’s with her mother’s approval. While that all happened, her mother got together with yet another guy (she has a new boyfriend every few months and lives on welfare) and this guy has beaten her and she currently has a restraining order against him. She still stays with him though although now she has a 1 bedroom apartment and claims to not be living with him but we have multiple pictures and texts proving she is still with him. She threatens to make her move 3 hours away every time the smallest thing doesn't go her way. My home has better medical care, income, and support in all areas over her mother and fathers. My fiancé has got her father’s approval but her mother goes back and forth between signing her off and threatening to come up here with a police officer and taking her.