He's not entirely certain Cullen's a demon anymore. He's still not entirely sure Cullen is Cullen, either, but: baby steps.

Without looking up, Alistair asks, "Hawke? The Inquisitor?"

If it's a demon, he's not sure which response will hurt more -- the ugly lie that they were slaughtered before making it through the rift, or the pleasant fiction that they're alive and well. If it's a spirit genuinely trying to help him, it'll tell him the truth.

And if it's really Cullen, he'll have witnessed everything firsthand. He'll know the answer, too.