Here's my explanation... some kind of religious and biblical thing.
A man is made of the body, the soul, and the spirit.
The body comprises the physical form and the external senses.
The soul comprises intellect and will.
The spirit is the one which gives life to man. It is literally called 'the breath of life'.
When a person dies...
His body ceases to breath.
It goes back to where it originally came from. It goes back to the dust.
The soul never separates the body. They stick to each other. When the body perishes away, so does the soul. The person's intellect, will, memory perish away with the body. The dead will have no more memory of everything he had in life. He will have no any share in everything done under the sun.
And finally, the spirit, the breath of life, goes back to where it came from. It goes back to the ONE who gave it to man.
The dead will remain dead until the end of ages, and the world. There will be no reincarnation or whatever for it is impossible for the person to take another form after they die.
That is the TRUTH. The evil, on the other hand, would do anything to go against that truth... so that the man will believe the lie.
The evil created ghosts or spirits of supposedly dead persons to confuse all men of the world who refused to believe the truth.
That's why psychics occur, spiritual mediums scattered all over the world, theories of reincarnation, and haunted houses became popular.
The man believed the lie and continued to refuse the truth...
...on and on.
That's why he is confused...
That's why he is afraid of death.