Then ask them: Can you prove God does not exist? When they say they can't, say: So your belief there is no God is an act of faith on your part.
You might want to read and discuss the arguments for the six ontological proofs for the existence of God and the six ontological proofs against the existence of God by Descartes. Your logic would not refute either position.
"You might want to read and discuss the arguments for the six ontological proofs for the existence of God and the six ontological proofs against the existence of God by Descartes. Your logic would not refute either position."
Then again, he might not. He could just be going by his playbook.
#109 ARGUMENT FROM LACK OF DISPROOF
(1) You can't prove God doesn't exist!
(2) Therefore, God exists.
#164 ARGUMENT FROM WE ALL GOT FAITH
(1) We all believe in something.
(2) Therefore we all have faith.
(3) My faith in God is no different from your faith that the sun will rise tomorrow morning.
(4) Therefore, God exists.