It's natural to be fearful of death after witnessing one
yourself.
I had 2 close kin passing away last year. The feeling is terrible.
You start to ponder about life and wonder when the scythe of the
Grim Reaper is gonna fall on you or one of your family members
next.
The solution? Do not think so much about it. Live life to the
fullest. There's no point worrying about something which WILL come,
but at an unknown time and place.
Meanwhile, just occupy yourself with the chores of daily life, get
a hobby or go widen your social circle. Of course, treasure your
loved ones. That's the most you can do. As some people say, when
it's your time to go, you can't stop it.