
I've recently had to have my old dog PTS. His quality of life was quickly going down hill and he had several problems.
I asked the vet if he thought I was doing the right thing as I wanted to make sure my desicion to have him PTS was 100% for the dog and not to make it easy for me so I didn't have to watch him get worse - the vet said if I thought I would only be watching him suffer/get worse then having him PTS was in the dogs best interest anyway.
I had already decided that at his age (14 & half years) I would not put him through any tests to find out what was wrong with him (possible kidney/liver failiure or tumor or several things all together), the vet said he would not want too anyway he thought it wouldn't be fair on my dog as any treatment would maybe mask the symptoms for a little while but not give him any quality of life back.
I broke my heart making that appointment with the vet and I cried my eyes out all the way there. I came back with a sad heart, an empty collar, but the feeling I had freed my dog from an old body that had just become a hinderence to him.
It was so peacefull, allthough I'm still very upset about loosing him, I'm glad I never waited anylonger. Keeping him going for longer would have been for me and not him.
I'm so sorry you have this awful decision to make.