She was afraid that it was a moral issue, and that was one of his weaknesses. He was Salander’s friend. She knew her brother. She knew that he was loyal to the point of foolhardiness once he had made someone a friend, even if the friend was impossible and obviously flawed. She also the friend was impossible and obviously flawed. She also knew that he could accept any number of idiocies from his friends, but that there was a boundary and it could not be infringed. Where exactly this boundary was seemed to vary from one person to another, but she knew he had broken completely with people who had previously been close friends because they had done something that he regarded as beyond the pale. And he was inflexible. The break was for ever.
Life Quotes And Sayings by Stieg Larsson, The Girl Who Kicked the Hornet's Nest