Jim, good luck with your cat as I had a cat name Buddy (16 years long....) and he really was like a son to me. When he died, it ripped my heart out.....

Yes, if you can, apply Neosporin or Aloe but by the sounds of it that he isn't eating and hair is missing or going matty, it may be getting near the end.

Buddy went blind but still caught birds and rats (don't ask....) and he would bump into things, stop, he would smile and them walk around the object.....
One other sign was our younger female (that he found on the street that was straving, but I watched him herad her all the way to his out the back door food and water dishes) would smell him and winkled her nose. I think she could smell the cancer or death and didn't like seeing him like that.
Good luck and remember the "Rainbow Bridge".....