Get him a Bike. Let him learn the clutch, throttle and gear sequence. Once he has that down, applying it to a car is simple as fark. I learned on a Motorbike when I was about 4 years old, given it only had 2 gears. I was driving a tractor at age 8 and driving car at about 10.
Agreed with all the previous posts mentioning learning to drive a manual and especially learning to "drive" on a motorbike if possible.
As a driver once you understand and have a feel for the machinery that you are using, navigating becomes natural and relatively easy.