The husband of my friend will die

A close friend of mine said to me on the phone that her husband will soon die from cancer.
They have two girls of 7 and 2.
My first thought is “This could happen to anyone,” which includes me and the people I love.
As it could happen to me, I worry about my health. I think I don’t really exercise as much as I’d like to.
This night I dreamt I was meeting the husband of my friend, and then I dreamt that my uncle, my brother and my daughter were ill.

C – My friend says: “Here it is. There is no treatment anymore.”
T – This could happen to anyone
F – Worry
A – Ruminate
R – I spend mental time and energy to worry ?

C – My friend says: “Here it is. There is no treatment anymore.”
T – This is so unfair for him
F – Shocked
A – Ruminate
R – I create a picture of him all alone in this

I think that what happens to him is a nightmare. This is so unfair to die so young. He will not see his daughters grow up. And all his friends will continue to live for a long time. I imagine him suffering and being stolen from a half of his life.
I also worry that the same could happen to me. I ruminate about illnesses (especially cancer).
I want to take care of my health and I think I’m not exercising enough (I’m already doing yoga every day, but I wonder if it’s enough).

Could you help to gain clarity? I think I want to feel negative emotions toward this situation. I want to be sad for my friend and her husband. Is feeling mostly worry and injustice useless? Thank you.