Well, all good things must come to an end. I just got home from being with my cousins as they had to put down their dog earlier today. Poor old guy was practically wasting away in front of them, he would barely eat, and couldn't get up and down their stairs any more.
The saddest part of this story is that they've had him since before my younger cousin (who is a year older than me) started school, and he is now graduating as a senior from high school this year. 13 years pass; a boy and his dog, starting an adventure together, and now finishing that adventure together.