Here is an interesting excerpt from a teaching that Lama Yeshe gave about seeing death as natural, which allows one to relax. He mentions:

So check up now. Wisdom is unemotional in nature. Fear of illness, impermanence and death is emotional; that’s why you cry. That’s why you can’t sleep. You think, “I’m going to die tomorrow,” and your stupid, relative emotions pump you up and push you so that you can’t sleep. True understanding wisdom sees illness and death as natural, so there’s no emotional nervousness upon hearing about impermanence and death.

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