I am really sorry about your friend.
I have no idea what happened, but many years ago, a friend of mine died–not in her sleep, but very unexpectedly. She was 26, had no known health issues, and seemed to be in pretty good shape.
My last conversation with her, just the day before, she was bitching about the manicure she’d gotten, which wasn’t up to her usual standards, and complaining about a stuffy nose.
So, she had a slight cold and a bad manicure.
She didn’t show up to meet another friend for lunch, and that friend eventually talked her apartment manager into opening the place up, so my other friend actually found her, and the police were called.
What they think happened: That she had undiagnosed asthma, had an attack, and just couldn’t breathe. There was some evidence that she was attempting to leave her apartment, and the cops suggested she was going out to get some help, but then she had a lunch date–except they think she was trying to get out much earlier (like 6 a.m., which would indeed have been very unlike her).
So short answer: nobody ever knew for sure, and the people who were in the best position to know couldn’t even be sure about the time of death.
The bottom line, our friend was gone. And it still makes me sad to think about it, but indeed she is forever in my memory.
Sometimes shit just happens.