Janis is extremely interested in Parson's potential capability to change the course of Erfworld's history. She has strongly encouraged Sizemore to remain Parson's friend and supporter, so that Sizemore will be in a position to influence Parson. Sizemore has so far followed Janis's advice, despite his own fears that Parson's influence on the world is likely to be terribly harmful. Sizemore believes that Janis is very wise, and he values her friendship highly. He views her as a moral authority.
When we first met Janis and Sizemore, Janis was trying unsuccessfully to teach Sizemore to use Flower Power, in return for a fee of 8 Rands. Since she is unable to teach him, Janis offers to waive her fee, but instead Sizemore insists on paying her 20 Rands, possibly because there is a good chance that he's going to die, and so won't need the money himself. Sizemore admits to Janis that he didn't really expect to be very good at the form of magic Janis was teaching. The fact that Janis had apparently never before tried to teach Sizemore Flower Power, and that he had originally agreed to pay her for his lesson, suggests that Sizemore and Janis were not particularly close friends before Parson was summoned to Erfworld. When Parson appeared in the Magic Kingdom, Janis moved decisively to take control of the situation, rendering Parson unconscious (perhaps so he wouldn't further antagonize the other casters) and offering a large sum of money to get Sizemore safely extracted from his link to Maggie and Wanda.
Unlike most of the other casters in the Magic Kingdom, Janis remains on very good terms with Sizemore even as it becomes increasingly clear that Gobwin Knob represents a major challenge to the existing social order on Erfworld. This is because she welcomes the changes she thinks Parson may bring, rather than fearing them.