In an atheist worldview, there is no afterlife.

You really have a problem with asserting what others believe. Atheists can, and some indeed do, believe in an afterlife.

People will not conceive of anything after their eventual death. Meaning can only be obtained through a comprehending organism. Thus therr is no meaning after death for an atheist.

You again assert he has to be alive for there to be meaning for him after life.

He can't perceive anything when he's dead so there is no meaning.

He also cant perceive other humans when hes dead, doesnt mean they arent still there.

An atheist by definition doesn't believe in the metaphysical. ( We're only speaking of atheists who don't hold superstitious beliefs and are consistent with their worldview. Atheists whose beliefs are congruent with the writings of prominent atheists. )

You are now literally trying to redefine what an atheist is just to justify your claims about atheists. Atheist just do not believe in gods