Get him to the vet - immediately. If the vet doesn't have any answers, get a referral to a vet who specializes or, if there's a college or university with a veterinary school near you, take him there.
And let us know how it goes. We've got another pup with seizures on the board, Buddy, a Husky pup who belongs to Iky. There's a thread that's several pages long about Buddy's problem. You might want to check it out.