If you ever misspell Brian Fawcett's name as Brain Fawcett, we forgive you. Jack is the brawn, and Brain is the brians. Er, Brian is the brains. The colonel, though, only respects brawn, so little Brian is pushed aside in favor of his brother. As Grann writes, Brian "lacked athletic prowess and was often, as he admitted, bullied by other kids 'into a stupor'" (17.72). Poor kid.
However, being brainy saves Brian's life. While Jack marches off into the jungle to die, Brian survives and becomes a curator of his father's legacy. Maybe this is why he never expresses anger or bitterness over being shunned by his father. Instead, Brian writes a bestselling book about his father's life and tries to find the members of the expedition via plane. Although he never finds his father and brother, Brian does piece together their story better than anyone else ever could.