Just tell her it’s great that she’s writing, and encourage her to submit them to magazines or other publications. Most of the published work is shrugworthy anyway, so she may achieve success.
That’s the starting point: “This isn’t my kind of thing. You’d be better off sending these to a more appreciative reader.”
Suggest they join a writer’s group where everybody’s work is critiqued by everybody.
Danielle Steele sucks but she’s rich. You never know.