Let's be honest here, Fitz had pretty much the perfect life before Sophie came to the Elvin world: A famous family, a powerful ability, amazing looks, a palace for a house, and beautiful eyes. Life doesn't get much better than that.
Keefe on the other hand grew up with awful parents, not many friends, lived in a dark tower, was looked down upon, and never recognized for the fact that he skipped a grade. All his parents ever wanted from him was MORE. How awful.
Sophie came into the picture as a broken girl carrying the weight of the world, only to find out she was literally a genetic experiment. She had to leave her family, get a new family, go to a new school, keep up her grades while struggling to adjust to her new life, and make new friends while dealing with enemies. (Not to mention the stress of having brown eyes in a blue eyed world)
Now let me ask you, how on earth could someone like Fitz understand what Sophie's going through? How could he understand tribulation and a past that is so jarring it's all they can do to not break down and cry?
Keefe has been breaking apart on the inside since book one, and has always been the one to see through her act. He can always tell when something is wrong because he knows what it's like to be in that situation. He knows what it's like to have a painful past.
While Fitz has always supported Sophie, he has nothing to comfort her because he simply hadn't gone through tragedy. Sure, his brother may be a traitor, but losing a brother compared to Keefe's life? Not even close. Fitz's life may have been flipped upside down, but it's still close to perfect.
Fitz reacts with so much anger to his brother because he doesn't do know to deal with adversity yet. He doesn't understand what's it's like and how to cope with it. So it takes it out on Sophie, for something that is completely out of her hands.
No offense to Fitz, but he simply doesn't know how to cope. Yet. Hopefully he'll get better at it. But that does not excuse him from the extra pain he caused Sophie. He could've angered her into breaking her mind! That wouldn't have gone down well, considering she's the only elf who can heal minds.
Sophie & Keefe understand each other in a way the the others cannot.
There's proof. Mr. Forkle said it.
