I think the connection between death and sleep is the nothingness you experience. I've grown up in a Christian home, and i've been taught that death is just a a very long, deep, and dreamless sleep until the second coming of Christ. Once he has come back, we will wake up and live a new life with him. In my opinion, I have always just seen sleep as being dead for a short time. A place or state of mind where nothing affects you or it's like a way to avoid life and all the problems you have. There are just no worries...except when you have those dreams nibbling on your conscience.