And so we deal with it. It works the subconscious mind while you work the conscious. This can result in dreams, peculiar habits, or even a change in your likes and dislikes. Death and everything related to it is a concern for us mortals. Just like that we are gone, but totally unaware, with no resolution or answer ever to be given.
Some people turn to religion, obviously.
Religion is as integral part of society as anything other, but even more so. We had religion even before we had government, before we had a civilization. And religion has been active in every civilization that has ever existed. One could almost say that a civilization cannot exist without religion. Communist Europe tried to disallow religion.