We had a similar issue, my stepdaughter slept in her daddy's bed since they got divorced. He lived with his mom and sister in a tiny house so he had ONE room for him and her and there was one bed. When he moved out with M. he wanted all of us to sleep together in one bed--NOT going to happen since she was already 6 years old! Plus she slept alone at her mom's house.
What you can do is allow her to sleep with you for a little while since it's a new house and she's transitioning. Give it a few weeks so you can get some rest. Then let her know she's a "big girl" and she needs to go to sleep in her own room. If she gets scared, she's welcome to come and sleep on your floor. If she sleeps on your floor she gets a blanket and a pillow. Don't make it too comfy. At first my SD thought this was so neat! Sleeping on the floor! But then it got uncomfortable after a night or two and she wanted a mattress. We said "no, mattress, but you do have a nice bed in your own room!" Eventually she chose, on her own, to sleep in her own bed.
Good luck! And remember, you can't control what goes on at Dad's. You made a request and he won't do it. It sucks, but that's how it works :(