If hemiplegia has no feeling, no exercise, and it happens to be a fracture here, there is no need for surgery at all!
Surgery is to relieve pain and restore function. I don't feel any effect at all. Is it meaningful to do it? Conservative treatment, but the possibility of healing is generally small, which may lead to nonunion (because the fracture caused by hemiplegia is difficult to heal), necrosis of the femoral head (because the blood supply of the femoral head mainly passes through the femoral neck, which will be necrotic due to insufficient blood supply after fracture), nonunion will form a pseudojoint, and the femoral head will be necrotic and dislocated. Because I don't feel anything, I won't talk about the pain, but these will mainly show that my thighs are not as stable as before, so just pay attention to them in my life.
Of course, if the economic conditions are good, you can also consider surgery. No need to change hips (that is, change bones). It depends on your father's age. If you are old and have other diseases, you can only play hollow nails to stabilize your bones. When the femoral head was completely necrotic, it was a long time ago, because the necrotic femoral head hurt first, and now I only care about the stability of the bone, so don't take it out.
Finally, if your father has feelings there and is not too old, then the first choice is to change his hips.