Greetings, and thanks for the question. My apologies for the delay, I just got in for the day and saw your post.
Sorry to hear about your sheep's condition. There are multiple causes for the problems that you have described, so I'd like to ask you a few questions in order to get you a thorough answer.
1): Is your sheep neutered?
2): When was he last dewormed, and which product was used?
3): How many sheep do you have in your herd?
4): What does his diet consist of, and does it include any grains?
5): Has there been any change in diet recently, or could he have possibly eaten more than normal?
6): Can you tell if he has any problems seeing?
7): Have you noticed any seizure like activity?
Thanks again, and I'm looking forward to hearing from you.