As the primary custodian of the teachings of Jamyang Khyentse Wangpo, Dilgo Khyentse was the de facto custodian of the vast majority of Tibetan Buddhist teachings. After the Chinese invasion of Tibet, his personal effort was crucial in the preservation of Tibetan Buddhism. Known as the teacher of His Holiness the Dalai Lama and the Royal Family of Bhutan, his life and teachings were an inspiration to all who encountered him.
Clairvoyance is really little more than a common skill that many people could develop if they truly attempted to work hard at such development. Those wishing to develop such skills should follow a few established steps that are quite helpful for developing the power of clairvoyance. And, yes, it can be quite a powerful talent to develop.