Hades bad word to use in Bible because it's Greek myth

A reader of my website sent me this email:

"brother, could you tell me why the nasb uses the word HADES IN JOHN 16.23 AND NOT HELL the kjv people say the word hades is a mythology name and not the right word it should be HELL thanks..." I answer this email on my King James Onlyism page.

Render unto Caesar

Is it "Render unto Caesar the things that are God's"? And what about separation of church and state?