Assessments by a social worker or nurse practitioner are also done in the States. I can't see a reputable (!) hospital discharging a patient to live at home alone if that person cannot demonstrate basic self care (dressing; climbing stairs, getting in & out of a car, bathing - all that fun stuff the hospital OTs & PTs teach us). Most often, the patient would be sent to a rehab center. In fact, the people in my parents' retirement community who have had joint replacements have been automatically sent to rehab for at least a week, & most of them are about the same age as Gem9's mother.
Jaz, you brought up some great questions for Gem9 to "casually" ask her mom. Doing one's own laundry, even with a grabber tool, is quite an experience, too. I bought disposable plates, bowls, & utensils before my THR so I didn't have to fuss with the dishwasher for a while, either.