I am sorry you are faced with such a tough decision. I know you have done everything you can for Chewy, and that he has had a loving and caring family while he was with you.
I will stand behind you 100% whatever you do, I know it will be hard.
Next time you're up this way, I'll give you my address, and you can stop in and meet my 2 nutcases--they should cheer you up a little.
Good luck with this very tough situation, I hope something can be done.
PM me if you need to talk.