A Non-religious reason that I believe in the afterlife

I've often read that as a person dies they see people who have passed before them.  I've also heard and read that people who clinically die, and are later revived also report seeing relatives.  I know two people this happened to.  Of course I believe that they are seeing their loved ones who are there to greet them from the other side, but scientist don't agree.  They say it's a lack of oxygen to the brain.  So here's my non-religious reason that I don't believe the scientist.
Why is it that everyone who survives a near-death experience never mentions seeing people who are actually still alive?  In every case, the person mentions seeing those who died?