User blog comment:FairyRaven/Fairy Tail Chapter 389: The Twin Dragons vs. The King of Hades, Review and Commentary/@comment-24277053-20140620113312/@comment-7418318-20140620162430

Only if doing so requires only little time.

When Keith arrived in the control-room, Lucy and Wendy were there and he chased after them. Then he fought against Gray until Alegria was used. So the only time when he could revive Crawford would have been while Lucy was fighting on her own, which is a rather small time-window, especially if you consider that Plutogrim crashed inside that window and I doubt Keith can revive a corpse while falling.