As long as his eyes *heal* and he seems content (eating and swimming like usual) I wouldn't kill him. He may not even suffer from vision loss... And if he does, remember he still has all his other senses at his disposal. Humans rely heavily on sight, so its easy for us to assume animals won't get by as well if they can't see... But this is truly not the case at all. -Especially if your Moor is still eating; blind or no, it's not hampering him. His nose is obviously still working!
I'd just watch to make sure the other fish in your tank don't bother him (any more then usual)... Otherwise, enjoy letting him live a long happy life!
*heal meaning they don't remain open sores, not that they heal perfectly and he has perfect vision.