Oh man, Im sorry. I had a dog that my parents bought a year before I was born. I literally grew up with that dog until, when I was 15, he, like yours, could no longer stand up. Putting him to sleep was the hardest thing I have ever done. I sat there and cried all day. And like Harshaw said, digging that hole was just torture.
So yeah, go get completely smashed. Had I been of an age to do so, I certainly would have.
Dammit I want another dog
