1 yr old cat diagnosed by vet to have feline lukemia

Question
What can I do to help him?  Is there anything I can do besides have him put to sleep?  He does not appear to be in pain, but does not eat and drinks very little water.

Answer
I need to know how ill he is.  FELV is not a death sentence, but I does make the life span shorter. If he is letharic, not eating for days and not drinking water you really need to sit down with your vet and speak to him/her about what needs to be done to make him comfortable.