Mary Miller reminds me of Jill McCorkle, which is about the highest praise I can give. Their styles of humor are very, very close. She also has a little bit of George Singleton about her. Mix this with some Eleanor Oliphant and I think you’ve got the idea.
The theme is human connection, but in an unsentimental rather than a sappy way. It’s being promoted as a book about a curmudgeonly older man who adopts a dog, but that implies (at least to me) that it’s going to be sickeningly sweet. Instead, Louis drinks too much, makes bad decisions, and has an unrelentingly snarky internal monologue that I found hilarious.