In the season's final episode, Roseanne reveals the entire series itself is actually a story written by Roseanne Conner about her life. To cope, Roseanne twisted major elements of her life for the story, which the audience does not discover until the final moments of the season. In reality, Dan's heart attack near the end of Season 8 was fatal and the Conner family did not win the lottery. A story arc running through the final season, that Dan betrayed Roseanne by having an affair, is revealed to be false. We learn that Dan's betrayal wasn't having an affair, but dying. - Wikipedia