Sometimes you need to suspend your disbelief while reading so you can enjoy the story within. This is one of those short stories.
It builds upon the original e-book by author Michael D. Harrison "Leaving Nora's Garden." Which was more aggressive and had scary sections. However, in this story an old man works at the side of his house, in a shed, building guitars as a way to pass the time. His service dog watches him daily and soon we find out they communicate as well as old friends do who care for each other. And they talk. Of course nobody knows about that aspect of their relationship. Over time other animals come into the story and of course, they can talk to each other. Just assume that it is a thing that happens; don't fight it, because its a story.
The important aspect of the story is the warmth of their friendships, the respect with which they relate to each other and the pleasant nature of their time together. The intention is to create a somewhat magic experience for the young person you are reading this story to, whether at bedtime or just together in the afternoon.
The dialogue is consistent with human interaction, but do not make the assumption a child won't understand. It may hit a couple notes where you have to explain to a very young listener, but that's the fun in reading to grandchildren of a certain age, I think. There is no crude material nor cursing in this book.
There is some education about the life cycle of animals, written in a gentle rolling forward of time. Some accurate nature descriptions. Please enjoy your time participating in this story and share it with your grandchildren.