As per your history, the main reason for his eye problems is retina which cannot be corrected by use of glasses or lenses. Retinal changes ( as it is mainly nervous in nature) are most often irreversible and so treatment part is also somewhat difficult. However, over the last 20 yrs there is much of the advances in medical and surgical retina treatment options. You need to tell us exact pathology as told by your doctor to know about the treatment options available for him.