system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 death and dying.  (After suffering the loss of a family friend and her [near full term] unborn child to a tragic auto accident, I need explaining death to my 5 year old daughter and 4 year old son).

If there ever was a time for ELI5 to live up to its name...now is that time, because as a single father of 2 I feel a bit overwhelmed at the moment.  (& as an atheist I would prefer to keep "God" out of the conversation, unless it is to use this tragedy to rationally discuss different aspects of different religions, ideologies, and spirituality ect.  The ex and her family are catholic, so they will be getting plenty of theistic input).  Thank you Reddit.
gpt
A body is kind of like a machine; you put food and water into it to keep it running, and it let's you move around and do stuff. But, like any machine, it can break down. And if it gets *really* damaged or really old, then it might stop working forever. We call this dying. Everything that lives has to die eventually; that's part of what being alive means. When the accident happened, [friend]'s body got too damaged to keep working, and doctors weren't able to fix it. That means we won't be able to see her any more. It's ok if that makes you sad, because it makes me sad too; she was important to us, and we'll miss her. But we can still remember her and be happy about the times we spent with her, and we can talk about her and how we feel about her being gone.

...

Then you ask if they have any questions and answer all of them as truthfully and simply as possible. Whatever happens avoid euphemisms like saying the friend is "resting" or "went to sleep", even if you qualify it with forever (as an atheist this probably won't be as hard as it is for those who are religious).