Obviously he couldn't be expected to help and do things of actual use. The universe might implode on itself. And Meg really needed to figure out who he really was other than that possible celestial being she was torn between stabbing in the face and screwing against the nearest surface.

"Please, you think I'd go to all this trouble over a fire? What do you think I am? An amateur? What does it look like I'm doing moron? Building an angelic wendy house." You know, usual every day demon behaviour...