Gliomas on both nerves is unfortunate and uncommon. Does he have neurofibromatosis? If they are talking about radical surgery that will take what's left of his vision, it doesn't hurt to get a second opinion from a well respected academic center. Unfortunately though, these kind of tumors wrap around the optic nerve and are virtually impossible to remove without sacrificing the nerve. Most grow slowly though and are not removed unless threatening other vital structures. He may have a more agressive form if they think removal is necessary.
Thanks for your response. They are getting a second opinion. He does have Neurofibromatosis. I have learned they are afraid of the tumors affecting his Pituitary Gland (I think).