17y/o cat drinking, but not eating, appears weak.

My kitty (Timer), is about 17 years old. I have had him since he was about 3... I adopted him from a place rescue center. They did not know his exact age.
   
He is indoors only.
   
He has had a very good, and healthy life, and only been to the vet twice in his life for anything (outside of normal shots, etc..)
   
Last time he was in was about 6-8 months ago, and they put him on antibiotics, at that time he was not eating, drinking, and was vomiting alot, and was diagnosed with weaker kidneys.. the meds helped, but the doc said that it would probably come back.. could be weeks or months.
   
This time he is drinking regularily, but not eating at all (that I can tell), except for a few treats, and sleeps way more that he used to, and no vomit, and constantly looks for place to hide... though his new favorite place seems to be the cold granite counter, and has very little energy. This started happening about 3-4 weeks ago.
   
I have a this feeling that its time (you know that gut feeling), that its simply old age, and he is looking for a peaceful place to pass away.
   
He does not seem to be in pain, he does like to held, and sleep on my lap.
   
Any thoughts from others.. I know 17 is a good age for a cat.
   
I dont want to lose him (who does?), but also am prepared to accept that his time has come, and I should just make things as comfortable as possible for him, and not keep him "drugged up" to only "be selfish" for my own needs.
   
Scott.
   

You could try getting an appetite stimulant for him. At his age, the side effects of steroids or the other stimulants won't really matter to his health.
   
That may help him eat & help him feel better to the end; also give him what he loves.
   
If he truly starts disappearing into caves & corners, yes, he's probably getting ready to die.
   
Take his temperature (there's an in-the-ear thermometer for cats & dogs) regularly. If his temperature is dropping below 101 degrees, then he's probably trying to die - this happened to me, once.
   
17 is an incredible run for a cat. But we all know that it's never long enough.

Things have gone down hill quickly. He seemed to respond to some fluids that I gave him via Sub-Q... but when I got home from work today, it does not appear that he will make it through the night.
   
He is extreemly weak, very little movement, shallow breathing, found a quiet corner to sleep in, and covered in what appears to be urine.
   
He does not appear to be in pain at all, just super tired.
   
I will spend as much time as I can with him tonight. I went to talked to him and told him that its OK to go now.