My wife's co-worker's son died for no apparent reason

I do not know if this is the right subject title to ask this question under.  I will try anyway.
Several weeks ago, My wife's co-worker died.  He was 28 and had no bad medical history.  He did not do drugs and ate healthy.  The story I got was that he woke up at his appointed time to get ready for work.   He told his wife that he could not breathe.  She and his sister started C P R. He died in the ambulance on the way to the hospital.
The autopsy showed to signs of anything.  Everything normal.  They are waiting on the blood samples.
I can not for the life of me figure this out.
   I smell a rat.  I could be wrong, but I can not see how a healthy fellow could just fall over and die like that.   It gets more wierd because there  was nothing out of the ordinary discovered in the autopsy.
Is it possible that someone poisoned him and it can not be traced?

[sstitanic2]

That is weird. I would have guessed heart attack or at least a heart ailment. A brain bleed is also a possibility. Poison it seems to me to be one of those things that would take a while. The tox screen should show something but some poisons take special tests. I would think the ME would refer this case to homicide. If nothing shows it will be listed as undetermined which the family should question and even contact homicide to get their input even if there is nothing they can do right away. Good luck Let us know