Final answer:
The question about the number of years after Helen's death lacks context, making it impossible to provide an exact answer without identifying the specific text referred to.
Step-by-step explanation:
The question refers to a period that the narrator "fasts forward" after Helen's death, which appears to be drawn from a literary context. To provide an exact number of years, the specific source material or text in question needs to be identified. Nonetheless, the extracts provided all mention different time frames, such as thirteen years, seventeen years, seventy-two years, and eighteen years, each relating to different subjects and storylines. Without additional context to determine which passage pertains to Helen's death specifically, it is impossible to provide a definitive answer.