In The Book Thief, death and freedom are entangled ideas. Death is described as a sort of freedom from life many times. Freedom from oppression is shown through death and his perspective more often than not.
Freedom, freedom from the horrors of the holocaust, the war against Germany, and struggle in every form is the ultimatum of any soul. Death, soon to be followed by many Germans and Jews, describe the ultimate freedom as death. The sky is a repeated symbol of freedom to the characters in our story. The sun is a hole in the sky, one which will lead to freedom, the desire of all things, the ultimate goal of life. Sunlight was another recurring symbol, one which was described as an ascent unto to the freedom, to the sky, the large, endless, free sky. Oppression, however, can never slip into the sky. When a Nazi shouts “heil Hitler,” it bounces right back from the sky as if it were a ceiling.
While what stands after the sky remains a mystery (it's hinted it’s God), what goes there, is no secret. Death has a direct passage to and from the sky. Whenever someone dies, a soul is taken to the sky. Death is freedom, in many cases. But in many others, people die and Death is never shown to come. When death talks about what humans have that it is jealous of, it says “the sense to die”.
Death may be seen as freedom, but death itself describes itself as evil, bad, sad, unfortunate, etc. In fact, many people died, without the character of Death making himself visible to the reader. Closure is the deciding factor in wether or not death is freedom. Even suicide is seen as freedom, but willing march toward victory in death is seen as lack of closure. Death will come to you one day, but will only lead to freedom if it is preceded by the proper life.