Told you I was going to get to this guy today.
First of all, rewriting these to fit the current mind flayer setup (let me know if you had something different in mind):
Extract (Ex): A brainstealer dragon that begins its turn with (all four?) tentacles attached and that makes a successful grapple check automatically extracts the opponent's brain, instantly killing that creature. This power is useless against constructs, elementals, oozes, plants, and undead. It is not instantly fatal to foes with multiple heads, such as ettins and hydras.
Improved Grab (Ex): To use this ability, a brainstealer dragon must hit a creature within one size category of itself with a tentacle attack. It can then attempt to start a grapple as a free action without provoking an attack of opportunity. If it wins the grapple check, it establishes a hold and attaches the tentacle to the opponent's head. A brainstealer dragon can grab a creature more than one size category larger or smaller than itself, but only if it can somehow reach the foe's head.
If a brainstealer dragon begins its turn with at least one tentacle attached, it can try to attach its remaining tentacles with a single grapple check. The opponent can escape with a single successful grapple check or an Escape Artist check, but the dragon gets a +2 circumstance bonus for every tentacle that was attached at the beginning of the opponent's turn.
Mind Blast (Sp): This psionic attack is a cone 30 feet long. Anyone caught in the cone must succeed on a Will save or be stunned for 1d4+3 rounds. The save DC is Charisma-based. Once the dragon uses this ability, it cannot use it again for 1d4 rounds.