Daniel's prophecies weren't written by Daniel. Isaiah's weren't written by Isaiah, either. I will have to check on Jeremiah, but I am sure it's true for him, too.
Prophesy isn't real. Later authors writing historical narrative as prophetic writing is common for those times. In case you didn't know it, now you do. This is fraudelent because they are trying to make it seem like God has given these men the power of prophesy when he has not. The atheists remain secure. Sorry.