I think I'm losing my boy

My Ben is 17. He has been in great health. Had to have his teeth pulled 2 years ago because they were bad. But he still thrived. On the 26th he refused his supper. Not necessarily out of the ordinary. He's been getting picky the older he gets. In fact when he sticks his nose up my other 2-2 year olds (Mercedes and Einstein) seem to do as well.
Anyways when he did the same Sunday I called the vet Monday and they came to see him Tuesday the 29th. As far as everything else went he didn't act any difference until Monday night. He wasn't demanding like he usually is. Didn't want his belly rubbed and at bed time he crawled under the sheets but didn't come up and lay under my chin. He stayed down low. Tuesday they said his kidney was enlarged he had a few ulcers in his mouth and had already lost half a lb. they Took blood sent it away but figured it was kidney failure. His blood was high in protein so they Gave us lots of drugs and special food which I started forse feeding him with. . Results came back Thursday and he was in kidney failure but dr was optimistic meds would help. Saturday he seemed to get worse. They came over and picked him up and put him on intravenous. He came home Sunday. Dr wasn't happy about his progress. On the Monday he woke me up stuffed up and when I took him to bathroom to work on his nose he fell to the ground Called vet. They came over (big after hour bill) and said he had food up his nose. Cleaned it out and he was sounding better. I was running home from work every 1 1:2 - 2 hrs to feed. Grown up daughter came home that night. Tuesday he woke even more plugged up. Dr said its was an infection and he might need lysine and extra antibiotics. Put him on stimulants to get him eating. On Wednesday he was getting no better and had lost some weight. So I increased what I was feeding him. Talked to vet and he put him on the lysine which I then found out my other cats may now be infected. So they're all taking it. He's growing weaker and weaker. He can't walk anymore without swaying. He won't eat or drink on his own. He try's to make it to the washroom but doesn't always make it. In fact if he does go he has to stop and rest or we pick him up. He and my other male have been snuggling a bit more then usual. My daughter said her goodbyes and went back home. Her boss was great when he found out and told her to go home for a few days and say goodbye.
After they left I took a hard look at my guy and my husband and I think we are being cruel keeping him with us. This hit home a little while ago when 2 things happened.
We took the mattress off our bed and surrounded it with pillows and blankets so he could still sleep with us and not be hurt. We put up the baby gate so he wouldn't try and go down the stairs and fall down. But he was laying on his pillow beside me when he moved. And rolled off his pillow and at the head of the bed was just the wall. He rolled into the wall (think goodness it wasn't much of a roll) then landed in an awkward position. But just lated there. I picked him up and cuddled him.
A while later back downstairs I was eating supper and then went looking for him. I finally found him in the kitchen tucked behind the garbage can on top of suppers pizza box. He had made it to his litter box but couldn't come back. I called the vet who will be coming over and if we can no longer save him then do what's best for him. Problem is my head knows this but my heart does not and I'm already making excuses on maybe why his legs aren't working right. That he won't eat or drink. And there's a part of me that has hope and looking and grasping at every sign. (A cat won't cuddle another cat if they sense they're dying?) he doesn't want to hide but remain beside or on me.
How can I know for sure that with the right time length the lysine and antibiotics he could make a full recovery. How do I make that decision to end his life. He's given us so much love in the last 17 years. How do I let him go?
I apologize for any spelling mistakes or grammar ones. Typing and crying on a small ipad screen makes reading almost impossible.
Does anyone know much about lysine and the "herpes" infection. His blood is clean now they said. His eyes and nose aren't running quite as bad. So the meds are working to some degree. What if we give up to fast? Or worse give up to late where his last days with us were painful for him.

I can't give you any advice on the herpes and lysine, but I went through the same agonizing decision about euthansia a little over a year ago with our almost-14-year-old Jamie, who had severe heart disease. In his case we'd gone through about 18 months of real ups and downs. He'd recover to some extent for several weeks, but then came the next crisis. As long as the ratio of "good times" to "bad times" was about 3:1, we continued treatment. In the end, he went completely downhill very fast and let me know he was finished fighting. When I took him in, the vet told me we might be able to prolong his life for a couple of days, but she felt I was making the right decision to let him go peacefully right then.

What it comes down to is quality of life. Massive treatment to extend life for days or weeks is just postponing the inevitable. Seventeen is a ripe old age for a cat, and from the sound of it, your boy is ready to go, without the stress of being constantly poked, prodded and force fed. You need to ask yourself if you're going to continue treatment for his sake, or for your own? If it's for your own sake, it's time to give him the last gift you can - a peaceful death in your arms.

I'm so sorry you're going through this.

We have a special forum for those who have lost, or are losing, their cherished fur babies, Crossing the Bridge, where we share our grief and our memories. One thread in particular, When the moment comes...
which was started by a member who's has been through it, may help you, as it has others. There's also one with info on professional grief counselors you can call: For those wanting to talk to someone, the ASPCA grief hotline

I wish you peace of mind.

I am so sorry to read this. Sounds like a very difficult time for you and your family.

I have used Lysine several times for my cats over the years. It works generally quite well I find. I put it in their food - thus important they are eating. I have read a few people say that their cats will actually eat the Lysine paste or gel straight, which in your case might be very helpful. I'm unsure if it comes in other forms.

I had an older cat who would have quite bad flare ups of FHV. The Lysine helped manage but never got rid of her symptoms. My younger boy has much milder FHV symptoms and the Lysine pretty much completely clears them up. It usually takes him 7 - 10 days of Lysine twice daily in food to get the sneezing, watery eyes and runny nose to clear.

I hope this helps somehow and that your sweet kitty is on the mend. It's so hard taking care of them in those last years and trying to know when it's time to say goodbye.