Sounds to me as though it would be better making a comic book or film ---script from that story.
The harsh realities of life gradually wearing down a key comic, from its minty-fresh, vibrant youth, the scars and physical damage inflicted by one harsh experience after another, ending with callous violation in old age by a selfish dog with impulse control issues, and, ultimately, worn-out and hopeless, barely clinging onto existence as a broken, wizened CGC 0.5.
It's a classic, heart-rending literary trope.