How do you prepare a 4-year old for death?

This was posted by an aquaintance of mine on Cougarboard.com. Being a parent, this hit me hard. Children are so precious to me, all of them, but the ones you make sacrifices for daily (wheather tiny or large) are even more special to you.

Before I post it, I also was saddened by a portion of the book "1776", which goes into detail of the beginning of the Revolutionary war. One section described the Americans Bombing Boston (where the Brittish had the town under seige) and the American soldiers wrote that the worst part about initiating war was hearing the women and children screaming in fear and pain from the bombing. They were only bombing less than a mile away, so they could hear everything. I cannot fathom what it would be like to have a child have to live through war, and yet I know it happens on a daily basis.

Here is what my friend posted:

Our good friends are about to lose their 4-yr-old son to brain cancer. This courageous, amazing little guy has been fighting the good fight for over a year now, but the cancer has become too invasive to battle any longer. The parents have brought him home, and are making him as comfortable as possible for as long as possible...

How do you prepare a 4-yr-old to die? How do you explain what is happening to him? How do you teach him what he should be expecting over these next (and last) few days/weeks of life?

And how, as a parent, do you cope with this?

Give your kids an extra hug tonite, and thank God for these precious gifts.