The tavernkeeper has adopted Tetula as a sort of mascot/good luck charm. The tavern has been adorned with four Placards of Wisdom (including "HANGOVERS ARE UNPLEASANT," which Tetula is too embarrassed to admit isn't official) and seven holy symbols of Cayden Cailean. A rather bad statue of him greets you at the door. Tetula drinks (and more importantly eats) for free as long as she prepares Mending and Purify Food and Drunk each morning and promises to channel if anyone gets hurt. She's excited to discover that she can adapt so well to her new job!
She is sipping at a beer because, ironically, she doesn't actually much like being drunk.