I would ask why we see examples of piss poor design. Why is there no padding on shins and funny bones, why are almost all attempts at reproduction failures, why has almost every life form that ever existed gone extinct.
Usually the answer is that we cannot know the Intent of the Designer. If that is the case, then the whole Concept of a Designer is worthless since we cannot predict the "Intent" of the Designer.
If he then pulls his usual Gish Gallop and tries to talk about prediction and Evolution, remind him the issue is not the TOE but rather supporting ID. Even if TOE fails at prediction, that tells us nothing about his imaginary designer.
But remember that the man is GOOD at what he does, he is experienced at deflecting reason and misdirecting the audiences attention. That is what he does for a living.
Aslan is not a
Tame Lion