Hello.
I understand your concern about driving or renting a car. Everything gets o expensive! If you have questions about the requirement for a car, I would call them directly and ask for an explanation and if needed, a waiver for the time you'll be there.
My husband and I are currently at the Healing Home for my 6th year heart eval. There are several vacant rooms in our casita and in others as well. $48.00 per night for those without insurance coverage. It has its pros and cons, but it is so close to the hospital. We drove up from Tucson, where we live part of the year, on Super Bowl Sunday. So glad it was all happening on the opposite end of Phoenix.
It is really beautiful here!
Good luck with making your decisions.