Quoting from the news article:
In response, Advocates for Faith and Freedom responded to the FFRF and pointed to the ruling in Silverman v. Hagerstown Suns Baseball Club, when a ballpark was found not to violate anti-discrimination laws simply because it offered discounted tickets to those who brought church bulletins.
I am not familiar with the Advocates for Faith and Freedom, but they apparently are a legal aid organization such as Alliance for Defending Freedom or the Thomas More Law Center. As such, they might be expected to provide pro bono assistance to the pizza parlor. However, their past court cases have all been in California, and their attorneys all seem to be licensed there. I am not sure they would be able to directly assist in Arkansas, although they may know lawyers in the area who could.