Unconscious works for me. Cool beans
Okay, seems we're agreed on that.
Let's try to figure out some parameters for this power. It likely should be (Su) since the Titan can use it unconsciously - plus it'll give it a better save DC.
We need a range and/or area of effect. In the adventure the "grey mists" appear soon after the PCs enter Andromidus's temple, which should give us a minimum range. However, the place is HUGE, with the entrance 700 feet away from the throne were Andromidus is slumbering, and an "inner entrance" 500 feet from him.
That suggests a range or radius of effect of about 600 feet, although that might be a minimum.
As for the area of effect, in the adventure he creates 5 illusory "sets", some of which are pretty large.
Set A - Forest, 470 feet by 360 feet.
Set B - Underground Passages, 120 feet by 85 feet.
Set C - Open Ground, 485 by 350 feet.
Set D - Caverns, 430 by 260 feet.
Set E - Three-roomed building, 35 feet by 30 feet.
If all those sets are existing in the same space within the "gray mist" they'll easily fit within a 500 or 600 foot radius. However the sets change each time the PCs visit them as Andromidus's dream about the situation they represent changes.
That suggests he's recreating a set each time the PCs pass through it, so the minimum dream size need only be the longest dimensions of the largest set - which is 485 feet.
So a range/area of 500 feet by 500 feet would fit the observed scale.