Single Parenting Support Group
Today being raised by a single parent is not uncommon. About three in ten children live in a single parent home. The most common type of single parent home is one with only a mother. However, single father homes are the fastest growing type of family situation; 60% growth in the last ten years alone.
I engage her in something she likes and then let the conversation start on its own.
I find that if I sit on the porch and read a book later on at night, she will come out and sit with me. If I give her enough time to start talking on her own she will start talking.
Make a point of having alone time with her and eventually she will open up. You can share your own stories with her; almost like you are confiding in her (make it age appropriate however). She will get the idea that it's okay to open up to you.
Continue to be her soft spot to land. She obviously feels "at home" with you. I wouldn't push her to return to dad, especially if he's abusive. That in itself is a valid reason.