He’s not eating hay or pellets and he’s unable to use his back legs. If that isn’t enough of a reason to drive two hours, I’m sorry but I don’t know what is. He needs a rabbit savvy vet immediately. If that means driving a while, so be it. You took on the rabbits – It’s your responsibility.

I’d get him to a vet as soon as you can. Even if you have to drive him that 2 hours for this first visit. And in the future it is VERY important he goes to a rabbit savvy vet. Rabbits show illnesses in different ways than a dog or cat does and it’d be easy for him to get misdiagnosed or untreated. His leg could be from an injury, it could be EC, it could be a bacterial infection. It would be important to treat all of these as soon as possible and I would strongly advise against waiting until the second. 

The first thing I come to think of when a rabbit loses control of his hind quarters is e cuniculi. It’s a parasite (a type of microscopic fungus actually) that many buns carry unsymptomatically. In some rabbits, the parasite invades the nervous tissue (spine, brain), or/and the eyes or/and kidneys. Loss of hind leg function is typical, another common manifestation is wry neck (head tilt).

It’s too long to wait until the 2nd, he should be started on medications asap. Treatment consists of a dewormer (panacur) for at least 28 days. Vets often give an anti-inflammatory (metacam) and sometimes an antibiotic (baytril) in addition to the panacur. It’s very important that the rabbit eats healthy food, so if he wont eat pellets or hay by himself, you should syringe feed him pellet mush or, preferably, Critical Care.

Here is some info about e cuniculi:

https://rabbitwelfare.co.uk/rabbit-health/e-cuniculi/
http://www.petcarevb.com/rabbit-veterinarian/rabbit-e-cuniculi.php

Here is a web page dedicated to the care of disabled rabbits: http://www.disabledrabbits.com/

It has tips about how to make life more comfortable for the bun, whether its temporary or permanently disabled, how to help it clean itself and other information.