Now to me this seems absurd. I understand that no one really knows what happens when you die so if you dream it, your dreaming a perception of what death is and feels like and what happens afterwards.
So lets figure out what's really going when you dream about your own death physically and mentally.
First what is a dream. According to University of California Santa Cruz.
The word "dream" has four interrelated meanings that follow one from another. When we put them altogether, we know what a dream is.
First, a "dream" is a form of thinking that occurs when (a) there is a certain, as yet undetermined, minimal level of brain activation, and (b) external stimuli are blocked from entry into the mind, and (c) the system we call the "self system" (the "I," the "me") is shut down. This may seem overly complicated, but it is worded this way because we don't just dream during sleep, but also on some occasions in very relaxed waking states when we "drift off" and suddenly realize we have been dreaming. Two careful studies have shown that people are awake (by EEG criteria) during these episodes. (The fact that we don't need to be asleep in order to dream may have some important implications. For example, it favors a "cognitive" theory of dreams over theories that talk about neurophysiological or neurochemical changes during sleep that supposedly produce dreams.
Second, a "dream" is something we "experience" because the thinking is very real and makes use of our senses -- especially seeing and hearing; because usually we are the main actor; and because a dream is sometimes very emotional (but not always).
Third, a "dream" is what we remember in the morning, so it is "a memory" of the dreaming experience.
Fourth, a "dream" can also mean the spoken or written "report" we give to others about that experience, which is the only way anyone else can ever know about another person's dreams (because they can't be seen by others or told about by us while they are happening).
So, to sum it all up, we can think of a "dream" as a report of a memory of a cognitive experience that happens under the kinds of conditions that are most frequently produced in a state called "sleep." But if you want it to be more simple, you can think of dreams as the little dramas our minds make up when the "self" system is not keeping us alert to the world around us.
Most people and mammals dream during REM sleep which is an important part of sleep that deals with learning. Infants spend much of their time sleeping and also spend more time in REM sleep and of course are learning at an accelerated rate during this time in their lives. We dream about 5 dreams on average a night although you don't always remember them. In fact many people don't recall their dreams at all which means that many people may have dreamed about their own death and just don't remember it. But of course are still alive today to not remember it.
In fact if you talk to many people, or as I have done gone around the web to find people that have dyed in their dreams, all of them are alive and well and many see the death dreams not as scary but enlightening and/or relaxing. Here's a thread with a bunch of these people. Although I should point out that it is possible to die in your sleep. Just not because of a dream.
The reason you can't die in real life when you die in your dreams from my just now research is because your body, in many ways, is disconnected. This helps prevent you from hurting yourself while dreaming. Like if you act out punching someone or something and end up just hitting yourself. This does happen occasionally but out of the thousands of dreams you have a year it's pretty rare.
So in conclusion from what I've read it is in fact absurd. Although I will point out that I didn't dream of my death last night and I am still alive. Don't know if there is any correlation there.