OP - I would line up a home health aide to help your dad for first couple of weeks at home and to be a second person in the home. Be sure that they have him learn how to do the stairs before he leaves the hospital. Be sure you have a strong man around to actually help your dad get home from the hospital, into the house and up to his room because it may be a challenge. I would suggest renting a shower chair which actually may work better in a bathtub initially where an aide could actually help him get in and out. Also get a shower head that can be handheld put on the shower he will be using long-term as he may prefer to use the shower chair in there for a time. (It is not hard to do.) It may be best to have an aide in the morning to help him get up, bathe, dress, eat breakfast in his room or on that level before heading downstairs. Depending on how he does on stairs, the aide could assist in getting him down to the main floor for the morning, and then back to the upper level for the first few days. Usually, you need to hire for 3/4 hours a shift. If all goes well and he does the PT exercises faithfully he should regain his strength.
My husband had a hip replacement at 63, and he used a male urine bottle at night which dealt with the issue of getting up to go . We also bought a 3-in-one bath chair, which could be used bedside if one was too weak to get to the bathroom or a fall risk say if the bathroom is small and hard to maneuver two adults in there. We found you could put the frame of the chair over the toilet and the arms acted nicely as grab bars until he was stronger. He was in good shape overall, but what we learned is that he had low blood pressure and the doctor's nurse never really noted it, so he was prescribed Percocet for pain, which he never really had. Anyway, a visiting nurse suggested he take it anyway "to be able to get the most out of PT, and he ended up having a full-out fainting. Thankfully, our daughter who is a PT was home for a few days and caught him using the bath chair. Then she had to instruct the young ambulance volunteers on how to use a backboard to get him out of a narrow bathroom. Motto is be sure his prior medical record has been read if there is any chance of interaction with medication.
For what it is worth, my husband has done the recommended 4 exercises after a hip replacement in bed before getting up in the morning daily, and he has never had a complaint.