So sorry to hear about Nugget, I replied when you first took him in and didn't expect any complications. I just noticed he is still in the news (via member introductions)
My friend(with house chickens) has a silky rooster that did the same when he was younger. Every day she thought he would die but, he didn't - he is several years old now. I don't know at what point he stopped having the seizures but, she said he also used to run a fever(?) he was so hot that it burned to touch him. She would cool him down with water and cage him(so he wouldn't get injured) until he stopped thrashing around.
He also had the wry neck and used to walk backwards with his head dropped between his legs, and do cartwheels (her description, not mine). He had the polyvisol infant drops, a few drops squeezed from vit. e capsules-can't recall what else.
I've read that some benefit from prednisone , given by vet and following his instructions but, she wouldn't take him to a vet. Sorry I don't know what the turning point was - it seemed like his bad days went on forever. But he is fine.
I don't see her often and she is pretty forgetful, so I don't think she would even remember when he came out of all this stuff. He came from a feed store as a pullet and fooled her on that too. I think the only reason she never put him down was because - only her dog goes to the vet, who ironically does have(and know) about chickens. Our friendship went downhill from this attitude & our arguments - she could afford it and her chickens were HER babies, the dog was just a dog to her. Go figure.