I am pretty sure that the use of “Delian healer” to refer to Apollo is called an epithet. I choose this figure because Delian was named so as the location of Apollo's birth is called Delos. Epithet definition says that it is known as <span>descriptive title. Hope you will agree with me. Regards.</span>
An epithet is a byname, or a descriptive word or phrase, that accompanies or replaces a name after having entered common usage. It usually has different meanings when used to seemingly real or fictitious people, divinities, objects, and binomial nomenclature. At the same time, it´s possible that an epithet is used as a descriptive title, such as Pallas Athena and Alfred the Great.
The “Delian healer” refers to the role of Apollo as a healer in connection with Paean.
Bueller's decision not to embarrass Victor advance the plot of the story? It adds to the conflict because Victor will have to admit to Teresa that he doesn't speak French. It leads to a resolution by making Victor look good in front of Teresa and giving him an opportunity to be close to her.