Yes, health preservation can be done in life, and it doesn't need to be done specially. As for the accidental death of your classmate, it is something that fate cannot control. Fate is a combination of order and disorder. We control ourselves, self-discipline, learn knowledge, improve ourselves and so on. This is the embodiment of order, and we can do it. Accidental death, what family you were born in, what environment you grew up in, etc. They are all manifestations of disorder, which we can't control but accept. Let us do what we can and accept what we can't control.