Then ask those same atheists if they are telling the truth or only dreaming.

Why? How does dreaming come in to the question of what someone thinks?
I know religious prophets have dreams of gods, do you mean the same thing happens here?
The idea isn't literal dreaming. The idea is a forced day dreaming, to make it seem reality.
Science talks about cause and effect as though it is the basis for everything. A scientist is great only after he has mastered seeking the causes for any effects.
Entropy suggests that complexity is waning. And, entropy seems to be universal as far as we can tell, even though there are flares of complexity now and again... flares which are culminations of combining of that which is even more complex.
If God happens to NOT be proven by this, God is highly suggested. So, what kind of day dreaming is it that atheists use to get them selves to so adamantly resist any idea that God exists, while at the same time so emphatically accept the sciences of cause and effect, complex universe, and universal complexity.
Everyone lies to himself one way or another. What strength of mind these atheists must have to lie to themselves in such a great way as to accept science, but resist the greatest thing science is showing them!

Ah. Concealed abuse, again. I'd thought you'd changed but it seems not.