Well that is interesting that you are curious to see how an atheist would act if Jesus came down from heaven to make an attempt to prove his divinity to us.
I would only ask him a series of questions if I had the opportunity, but only to see how he would answer them.
First, I would ask if God is omniscient. If he answered yes god is omniscient, then I would ask this: If god is omniscient, then would he have the power to see the end at the beginning and everything in-between? If he answered yes then I would ask another question: If god had the ability to see everything before it happened then why would he create an angel (the devil) who would go against him? If he knew that "Satan" was going to turn on him, then why would he create him in the first place? After all, it was because of the "snake" tempting Adam and Eve that resulted in original sin which damned all the nations to come. I mean, if a god really was omniscient, then was his divine plan to create a creature to go against him so he could justify the fall of man? Never helping humanity??
Or is it that he is not omniscient and didn't see the bad results until they happened?
Is it that he seen the evil to come from his creation, but lacked the ability to change it?
If he is all-powerful, then can he change his all-knowing mind? If so, then he would not be all-knowing; or, in other words, omniscient. If he lacked the power to change his mind, then he would not be omnipotent.
The problems of god are very profound and this truly is a small sect of questions concering religion and god. If you would like to raise questions, please do.
I haven't slept in 20 hours... Goodnight