Use the noun quietus to mean death, especially when it's seen as a relief.
Quietus is a poetic, old-fashioned word for death. It's a way of viewing death as an "eternal rest," or as a release from the turmoil of life, and also a delicate way to refer to the fact that someone has died. Shakespeare used the word quietus in his "to be or not to be" soliloquy in "Hamlet," although there is disagreement among scholars about whether Hamlet was talking about suicide or the settling of debts.