Re: Battery replacement?
If he still does it, the best way to see the (south rim of) the Grand Canyon is Marvelous Marv's Grand Canyon Tour. There is a RV park just of I40, about 30 miles west of Flagstaff (Canyon Gateway, perhaps). They belong to Passport America, so are cheap if you are a member. And they provide a discount for Marvelous Marv's tour if booked through them.
Marv will pick you up (at the park), take you to the Grand Canyon, show you all the best places, give you lots of neat information, answer questions, provide for shopping, and take you back. And the best part is, avoid all the crowds and hassles you often run into on your own.