Tom O'Brien was a horse racing enthusiast. The horse racing world mourn his death at his passing at 39 after a cancer battle. Many publications called him a fantastic person. O'Brien won races at the Cheltenham Festival. The Guardian and 7NEWS reported his death after a courageous fight with cancer. At Bangor, a close friend called him a champion and a skilled jockey. Yahoo News Australia said O'Brien was the second jockey to die in a short span. Tributes continue in the world of horse racing.