I have this really old dog, 16 years old to be exact, and my parents are saying it might be time to put him down as we have to put down his sister who has lost bladder control and may have cancer (lots of bumps all over her). He is eating and drinking just fine, He's just old and I can feel his ribs and spine; I'm feeding him soft food now in hopes of putting a little weight on. He's in no visible pain. He's blind and almost deaf; he runs into things a lot. He can still hold his bladder like a champ though and seems pretty happy. He's a really good dog and doesn't get into trash and the cat box like the others do. Do I wait until he is suffering? Do I see how the winter affects him? I really don't know...