If you absolutely want to be able to tie his ability to a power there are a couple listed in the Custom Power thread that could be used.
Reality Warper [-2]
You are able to shape reality to your whim, as if the entire world was simply a dream of yours.
Skills Affected: Discipline
Musts: Demesne
Effects:
Sculpt Reality. You can always alter reality as if you were in your personal Demesne, though with slightly reduced effectiveness. This allows you to make declarations and maneuvers related to the nature of the local reality with your Discipline skill. The duration of the changes created by this power is variable, but it's generally at least one scene.
Offensive Sculpting. You may use the world around you as a weapon. This allows you to make Weapon: 0 attacks with your Discipline skill against anything within your line of sight. You may make spray attacks with this power. You may also attack entire zones with this power, although you suffer a -2 penalty to do so.
Improved Sculpting [-1]. Your Offensive Sculpting attacks are now treated as Weapon: 2.
Powerful Sculpting [-1]. Your Offensive Sculpting attacks are now treated as Weapon: 4, and any scene aspect you place with Sculpt Reality is automatically made Sticky.
Counter-Conceptual Interposition [-1]. You may use your Discipline skill to defend against physical attacks.
or
Dream or Reality [-2]
For you the lines between Dream and Reality are blurred, so much so they are almost non-existant. You live just as much in the world of fantasy as you do on planet earth. You are able to bring your control of your Demesne into the mortal world. You are able to shape reality to your whim.
Skills Affected: Discipline
Musts: Demesne
Effects:
Sculpt Reality. You can alter reality as if you were in your personal Demesne, though not as freely as you would be able to in the Nevernever. You can roll Discipline to place scene aspects as normal, and can even use discipline to physically attack using the (now) mutable nature of the zone against your opponents. However, your attacks are all weapon: 0. Any change you make is impermanent, and reverts to its original state at the end of the scene, however, you may spend a fate point to make a change permanent (or more, at the GM's discretion).
Rapid Eye Movement. When you use this power your eyes flicker back and forth as if you were sleeping.
Illiteracy. You are unable to read, it is not because you do not know how, it is just that your brain is unable to correctly identify the symbols on the page. If you somehow loose access to this power, you will be able to read (if you were previously able to).
Improved Sculpting -1. Your attacks are now treated as Weapon: 2.
Powerful Sculpting -1. Your attacks are now treated as Weapon: 4, and any scene aspect you place is automatically made 'Sticky'.
Or if those don't do it for you, greater glamours is practically a green light for declaration and creations. And the books rules barely crack the surface of leveling it out for playing.