5 year old wants to stay with her dad

Me and my husband are separated and I moved in with my sister and bil. We currently do not have a custody agreement yet because me and my husband haven't been to court so our daughter has been going with him on weekends. When I tried to pick her up Sunday she was screaming and kicking that she didn't want to go back and when I asked why she said she doesnt like her uncle. My sisters husband is a weird dude. I'm not sure how to explain it. He just says and does weird stuff and has a habit of making people uncomfortable. Example when they were dating and we got drunk he told a story about the time he was pulling on a Yorkie dogs ear and it bit him and he got so mad it bit him that he kicked the dog so hard it died and his sister(who's dog it was) never found out he killed her dog. He told that story laughing about it. We get along fine but he's just strange. I told my daughter she doesn't have to be scared of him but she continued to throw this screaming fit until I gave in. I decided to let him have her for the week since he only gets her on weekends and he called asking if maybe our daughter should just live with him if she doesn't like being there. I said no. I want her with me. But am I being selfish? If she doesn't like being here so much because of my weird BIL is it selfish to make her?