Thankfully, Lynn Plourde spoils the ending by stating up front that the dog dies. Because of this, the reader constantly anticipates the bad news. Don't let that dampen your desire to read this great book: there is plenty of great stuff in between the author's prophecy and the reality at the end.
From the author's website:
To be honest, I never dreamed of getting a dog. Maxi was a bribe from my parents.
I hope Lynn Plourde's other works are as pleasant as this one.