Christian argued that everything must have a creator

[athrock]

There are many forms of that argument, the one to which you are referring is called Kalam, and is more appropriately an argument for the existence of Allah, not Yahweh, Ath.  Christians do argue both your variant and many others which do not share that provision.

You're right, Rhythm. I did have the kalam in mind, but there are other variants.

The response to the believer would vary somewhat depending on which version he chose to argue.