This article is a collaboration between Fortune and ProPublica, a nonprofit investigative news organization. At a House hearing last year on post-traumatic stress disorder, a private organization showed up with an ambitious plan to help suffering veterans. The Cohen Veterans Network was opening a chain of free mental health clinics across the country, backed by $275 million from hedge fund billionaire Steve Cohen. By contrast to the high-profile scandals at the U.S. Department of Veterans Affairs, the Cohen Network claimed 96% client satisfaction.