I still don't know why a dog's purpose was this. I think the expectations of a dog might be a bit too high. And there is a second book so in the end he didn't fulfill his purpose, I think.
The point of view is funny but simplistic. The reading level seems to be somewhere at late primary school level, but the dead body's and other things that are less pleasant make it too mature for that level. So to me it's an uncomfortable conflict.