Psychic. Empathy - receptive and projective - and 'polite' telepathy.

Very strong empathy, particularly with his brother, but even unenhanced he's capable of sensing the most powerful emotion a person is feeling if they're within fifteen meters of him, though he can't project to anyone but Jack unenhanced. Enhanced, he can overwhelm anyone within roughly sight-range with his most powerful emotion at the time (and will, whether he wants to or not, when emotional enough, until he learns to control it), can also sense the emotions of anyone within that range, and will eventually learn to enhance or suppress specific emotions in others within range without feeling them himself. Overuse of the enhanced abilities leave him headachy and emotionally dull.

His telepathy is polite, by which I mean he can only hear what others are thinking if they want him to - they need to direct their thoughts at him, specifically - using his own telepathy, within a fifteen meter radius, unenhanced - in his brother's case it's difficult to tell, considering Jack's own abilities in the area, but he can hear him within sixty miles, the same as Jack. Enhanced, all that happens is his range increases significantly, making him useful as a receiver but little else. Overuse of the enhancements leads to mind-rending headaches.