The doc recommends a rehab facility for 10 days, but insurance won't pay. Any tips?

In my experience, the first response the ins co will give is almost always "NO". Don't take that for an answer.
Make a calling log. Log what time you called, to WHOM you spoke, what they said, what you said. Go over their heads. Call often. Have the drs notes handy to fax if necessary. Fight them. Ins cos don't want to pay. Period. Your hubby can't come home with a bilateral hip replacement! A week or more in a rehab facility will give him better skills to maneuver. It's good that he was in good shape before, that will help him, but in my whole life I have NEVER seen a dr release a bilateral hip to home after only a few days in the hospital.

By in house, i mean in- patient

Wait. The insurance company will pay for REHAB. it might be in a place that is also a nh, but inhouse PT is MUCH better than home PT. You want an acute rehab facility. Better equipment. More motivation to get out.

Please make sure he gets into a good rehab facility. He will get much more therapy than home care provides and he will have a better recovery. Injured athletes receive different forms of therapy several times a day. It makes a huge difference.

Well you call up the insurance company and give them a piece of your mind. Demand a supervisor. Do NOT bring him home.