My 21-yr-old cat Muzak has just gone blind. My vet says come in tomorrow for an exam, but that it's very common at his age. I've read about how to care for a blind cat, and how he will compensate by using his hearing and smell. However Muzak has not been able to smell anything for a year. His hearing seems just fine, but wow... Are there any things I should be doing for a cat who's lost those two senses?