He looks a lovely Dog, not much comfort to you now but the pain will pass, gradually but the nice memories will still be there. .Feeling very empty at the minute but know that I done the right thing as couldn't leave him in pain. This was Buster taken a few weeks back, you wouldn't think that he was 14 or that he had a stroke 12 months ago as he recovered so well.
Hopefully with time , in the future you could consider a new pup.