I'm going to throw this out there. I had to do some research on what is more cost effective hybrid or diesel vehicles. If your dad does most of his driving in the city, diesel is the way to go. Hybrids usually get worse mileage in the city than on the freeway, and from my research at the time (a little before Christmas) diesels cost less and got almost the same miles per gallon.
That said, and being the Jeep lover that I am, I would get a diesel version of what ever Jeep fits him best
That said, and being the Jeep lover that I am, I would get a diesel version of what ever Jeep fits him best