Here is a link to a picture of a severely affected Chi that has strabismus as a result of the hydrocephalus. I thought the eyes could be affected by the excess fluid and this picture from petplace.com shows it.
PetPlace.com
There would need to be a shunt put in place to allow the fluid to drain into the abdomen away from the brain. I'm sure your vet will have more information as to whether he is a candidate for this procedure. Will keep him in my prayers.
Also wanted to add that for those with weak stomachs you may not want to look at the photo.