My husband is in a rehab facility and keeps telling me that he wants to come home. How do I respond to that?

With honesty. As in "I am sorry hon, but you cannot come home right now. If you work hard and get better they might kick you out early, but right now you are where you have to be to get better".
You tell us very little. So I assume that you are speaking of someone who will come home after rehab. I wish you the best.

Physical therapists can come to the house.

Tell him the medical team will decide when that can happen. Don’t accept being responsible for him being there. Change the subject after answering.