His previous bookstore had also a gallery space for rent, so it may be the case that this new store's model is actually closer to a gallery---author or sponsor may pay some fee. Just guess; I couldn't find an official document stating so.
I used to work at an independent bookstore that had a niche for local and regional(WV/Appalachia) authors and stories. This worked great as we were in a tourist area, so the influx of new customers was readily available.
For local customers we offered custom orders, to address issues with limited supply. Though it would be cheaper to go to Amazon, a large portion of the community are artists and craftsmen so they liked to encourage the local economy.