I have never traveled further than 3 hours with the fids, but I agree with Shawna... frequent stops are key. When you have the dogs out for a walk, let someone stay in the car and let Kai out for some playtime. They have special perches for car seats, maybe get one of those and he can even hang out with the kids while you drive. If you don't have a carrier already, a cat carrier with a hole drilled in it, then a perch placed in the hole like you would in the cage, it makes a great carrier and the darkness will help Kai stay calm. Put a few foot toys in there, and my best advice for food is fresh food... veggies, fruits, whatever! Something that has natural water, as Shawna said, since water is not exactly easy to keep in a bowl in a car. This is how every bird I ever got through shipping was sent: lots of naturally moist food.
Best of luck with your move!