You know I just went back and read that your friend has other birds. It's a good thing that they will have their own coop. The little sight-impaired one will do better that way.
I have two older brahmas that are partially blind and had a young brahma that was completely blind in one eye. They do fine as long as nothing is changed in their environment; meaning nestboxes, feeders and waterers should not be moved around. Free ranging involves a larger danger to them than...