In "Barn Burning", is there a way to read the story in which the reader can view Ab as an empathetic or a sympathetic character?

I believe that this question is asking whether or not a reader can empathize and/or sympathize with Abner Snopes. I do not think the question is asking whether or not Abner himself is an empathetic or sympathetic person. If the second option is the question, then I think the answer has to be "no." Abner is a selfish and malicious character that doesn't focus on anything other than getting what he considers what is or should be his.
Despite Abner's unlikable qualities, I do think it is possible for readers to empathize and/or sympathize with Abner Snopes. Part of those feelings are dependent on the individual reader. If a reader is "down and out" and struggling to make ends meet, then I think that reader could find a lot of common ground with Abner.
While Abner may not have been the most honorable man fighting during the Civil War, he was still wounded. That wound has crippled Abner a little bit, and it makes sense that he harbors anger and resentment toward the people and circumstances that caused the wound in the first place. It's also likely that the wound causes him discomfort and pain all these years later. That pain could possibly contribute to Abner's overall miserable attitude. Anecdotally, I've been guilty of that myself after my knee surgeries. Pain a month after everything was supposedly fixed just made me irritable. That personal experience helps me to empathize with Abner.
Another possibility for Abner's anger at the world could be his socioeconomic status. As a tenant farmer, he is forced to use another person's land and grow their crops. Abner gets to keep a bit of the crop and hopefully sell it, but his work is going to make someone else rich. When Abner defaces de Spain's rug, Abner might be standing up to de Spain and showing what he thinks about de Spain getting rich off of Abner's hard work. That's a bit admirable and in some way makes him a likable guy. Unfortunately, Abner never considers how the consequences of his actions will affect his family.