Why are you making sacrifices to stop him being put down?
I suspect you're not doing him any favours with your sacrifices, and he might not thank you if he knew.
You can't really tell how much pain he's in, and yes, the medication might mask the pain but dogs are masters at hiding pain. Being incontinent and dragging his legs around and making them bleed sounds like hell for him.
Quality of life is all a dog has and there are worse things for a dog than being pts.
If I were him, I wouldn't want to live like that.
Sounds very much like it's times to let him go. That's certainly what I would do.
Forget what other people feel about the situation, they're not living with an incontinent dog and they're not feeling what the dog is feeling.
Far too many people keep their animals alive, usually for selfish reasons, for far longer than is fair or acceptable.
There's an expression relating to putting animals to sleep, something like: Better a week too early, than a day too late. Perhaps a bit trite, but it's very true.