Girl Accidentally Kills Mother and Sister in Guest House Fire

by Anonymous

What's the movie where the youngest daughter accidentally starts the guest house on fire where her mom is staying because she's very ill?

Her sister is inside with the mother. The dad is having an affair. Through the whole movie, we think the older sister is alive, but at the end we figure out that the youngest daughter has been committed/released and is seeing/talking to her dead older sister that she burned?