I've always loved Nanook's sweet, happy face. It's never easy deciding when to say goodbye. All I can say is try to focus on the loving him and making those final days or hopefully months some of the best, and when the time comes you'll be able to remember those plus all the others you've collected over the last 15+ years. Initially you won't be able to do that without a lot of sadness and tears, (it took me months before I could even think of my RB terrier, Sandy, without tearing. He passed away a couple of days shy of his 16th birthday.) but eventually you'll be able to think of those memories with a smile and know he had a full and happy life. He's trully a special boy and my prayers and thoughts are with both of you. Give him a big hug for me.