God is dead means, that christian moral is dead... and it should be revaluated... so, if yo use Nietzsche's name, nothing, that haven't existed cannot die...
Well if you are thinking where is God spending its afterlife then that is just silly. Nietzsche writes in "Thus Spoke Zarathustra" that after the death of God our churches are all his tombstone and grave. So check under them to see how God is spending its afterlife. As well... Based on Nietzsche's eternal return, the 'moral' period of God will return anyways, so do not fret if your worried about Gods afterlife. God will be back on top of the world in no time
If God is dead but endures in an afterlife, then.... What's the difference? I mean, He was so much more than alive to begin with, it's as if He was already living in an afterlife. Has He moved on to another plane of existence? And can't He do that anyway? If He's dead has He lost the power of creation? It's all so mind boggling!