The appropriate action for the nurse to perform is to SIT WITH THE CHILD FOR AN HOUR IN THE ROOM.
From the question given above, we are told that the child is immobilized, which means that, his movement has been restricted in order to allow for the healing of the injured hip, thus, he can not be allowed to go to the play room. Arranging a visit by a cooperative child from the same unit may not work because the children in that unit too are there because they need medical attention and may not be in the mood for play. Putting a phone in the room is not a feasible solution to an eight year old boredom. Therefore the best the nurse can do is to find time to interact with the patient in order to make the hospital stay more lively for him.