Hi Mike. I too lost most of my sight due to the Graves’ disease but it has now returned to almost normal. The standard procedure for treating this is usually Steroids at first to reduce the swelling and improve sight, next is orbital irradiation to attempt to stop the progression of nerve damage, and finally as a last resort, orbital decompression surgery.
I have no idea of the implications of his age with the treatments but hopefully he is under the care of a good Ophthalmologist.
Bruce