I can personally guarantee that this piece is 100% non-fiction.My course also focuses on narrative writing techniques.Does 'Storytelling' have to imply fiction?In Chinese "story(故事)" just things happened, it can be real or fiction .
The term that has no connotations of fiction is probably "narrative".
I think many languages have closely related words for fictional narratives and nonfictional narratives.
E.g. if you said someone was good at "storytelling" as a skill, then I would expect it to be most likely fictional. I agree that "tell you the story of..." could easily be nonfictional.