Problem is people's approach to your gifts, first; your parents. If they say continuously that you are gifted, very smart, very beautiful, adorable etc and you can do anything you want because you are so smart, you are most likely doomed later in life.
Now, my step-son about to finish high school. His mother, always complimented him starting from kindergarten. He was smart all along, did all problems from his mind easily without much effort. His parents and teachers complimented him everyday. He was happy, and proud of himself to be smart, his parents were also proud.
High school required more disciplined work. He couldn't make it, too many distractions around. He was thought to be a very special person when he grow up, but now, he is below average, and sadly, he accepts that even though he had the potential. I see how he will fail more in college, and can't help.
My only difference from him was that he is failing in high school, I failed in university.
I have a small daughter, 4 years old, and I am afraid as hell not to spoil her. She looks very smart and gifted. I always say she is not gifted, she is just normal. I don't want her to be very special person when she grow up, I want her to be happy and healty, that's all. Only thing I am trying to do is not to say her that "she is gifted, she is very smart".
I don't know how to solve his brother's problem. Looks it is very late.