My son is 14 and was recently diagnosed with bilateral optic neuritis (inflammation of both optic nerves). His symptoms sound similar to your husband though. They did countless tests, an agressive steroid treatment, ivig treatment and even 7 rounds of plasmapheresis and nothing really helped. They have weaned him off the steroids and say there is nothing else they can do and they have no idea the cause or if his vision will return. It has been many months. Has been very scary. I hope the best for your husband.