The Body, Soul (Spirit ) and Mind make up the Person. The spirit lives in the body and hence gives life to the body.
Without the spirit the body is described as deceased, it has no life in it. Interestingly when a person is alive the body is identified through a name. However when the person is dead the body looses the name.
For instance when Joe Blow is alive he is called Joe Blow. When he is dead the language change. He is now identified as the Body of Joe Blow.
So if we go back to what makes up the person we can confidently say that when a person is alive it is the spirit being that gives the body life.
Not only that we can confidently say that it is the spirit that talks but through the body. Without the body the spirit will not be able to talk. It is the spirit that makes the body function as we know and see it.
The mind is that emotional component of the spirit being. The ability to be Happy, Angry, Sorry, or Rage it is the mind that makes that happen.
This emotion is expressed through the body. Different emotions expressed differently. Can be either spoken or through the body language.
So what happens to the spirit when the body is dead as we know it.
The question is where did the spirit come from and lived in the body. The body we know decomposed and become soil.
But what happens to the spirit? We can easily say it went back to where it came from. So from where?
Those that believe in God know that the spirit is either buried with the dead body or is in hell awaiting the return of Jesus and judgement of God.
On this day those that are alive and those that are in the grave will rise and meet Jesus in the sky. Everyone will then assemble before God including those that are in hell for judgment.
The Book of Life will be opened. Those whose name are not in the Book of Life will be casted into the lake of fire.
Those whose name are written in the Book of Life will spend eternity with God.
In the contrary those that do not believe God exists have their explanation as to what happens when the person dies.
Whatever it is science has proven beyond doubt that the Biblical God exist and is the source of life and the spirit being of a person. He also created the body for the spirit to live in.
Every thing that He did was for His own Glory.