Can modern medicine regrow an optic nerve / treat an autoimmune disorder?

[BlasterMaster]

So, yeah, I have a relative whose auto immune disorder pretty much cost him 75% of his vision (it literally ate one of his eye's optic nerves and was in the process of assaulting his other eye's nerve before it was stopped). My question is, is there any medical technology or procedure that can possible help restore my relative's site by regrowing and reattaching his optic nerve (and possibly repair whatever damage was done to his eye)?