I don't know if putting a pin in the hip is different from replacing a hip, but my jw mom had to stay in the hospital a week longer than her non-jw sister after having a hip replaced. My "worldly" aunt was put in a few days and already getting physical therapy. My jw mom was in the hospital for about two weeks to get herself built back up due to blood loss.
I hope everything goes fine with your mom. What a shame about your older sister!