Dog Warts turned out deadly

Sarsi was a healthy dog for 11 years until some warts popped up on some parts of his body. I asked the advise of a veterinarian, and got two more second opinions (of course vets, too) and all of them said that treatment was not necessary because my dog developed it due to old age. Multiple warts appeared on his body but which did not affect his appetite, though sometimes we saw him limping when the warts started to erupt. I also asked the vet if it can be removed surgically but I was told that he cannot afford to undergo another surgery due to his age, and because he underwent his 3rd surgery early this year (the first two were different minor problems that needed minor surgeries some years ago) . I felt assured that there was nothing wrong with Sarsi until one day his appetite changed --sometimes he ate a lot, sometimes he just tasted his food --and when he totally missed  a meal I brought him to the hospital. Sarsi was confined for three days, but the vet said his vital organs failed (liver and kidney) and they suspected that there were warts on his internal organs, and sadly on the third day he can barely walk. I can't stand seeing him like that so I decided to give him rest, which I was told would be the most humane thing I can give him.

I was guilt ridden for a week, thinking why I gave him up.

Warts on his leg.

Warts below his right eyelid and lower lips.