Let's be real shall we? Even when atheists attend the funerals of family members, they grieve! Is this grief a mere meaningless chemical process in their brain, or does it have meaning? You see, atheists like you live a hopeless dichotomy in that there can be no real meaning if there is no God - all is just a machine and man is part of the machine; but the atheist can't live that way! They live as if the love they have for their wives and children has meaning! They consider their wife and children to be valuable persons and not meaningless masses of molecules! They live as if the lives of their loved ones have meaning They live as if the death of a loved one has meaning! They live as if grief has meaning! It's a hopeless inescapable dichotomy. They cannot escape the mannishness of man.
Tell you what, if grief is meaningless, and you are a machine, then that feeling of grief is just a chemical process in your brain - nothing more. So, the next time you attend a funeral of a loved one, just keep telling yourself, "what I feel is meaningless," and see how far that gets you.