Geezus this one hurt for sure! It's sad and depressing and tragic. You feel the guilt and the desolation that is weighing so heavily on Derek. To really explain this further would negate the full impact of this.
But I do think it's worth reading! In the end there's an acceptance of the situation; it's bittersweet and hopeful - you know these two will be together forever - definitely, lessening the sharp edge of loss and irreversible change. Such a succinct story amazingly leaving a lasting impact.