It is impossible to imagine nonexistence, so in our imaginations we are all immortal. Stoicism teaches that it is irrational to fear something we cannot change or avoid, but rationality is a learned skill and our consciousness is not rational, so we fear death.
I don't believe there is anyone left in the world who has not lost a friend or family member to cancer. It is a horrible wasting disease in which your own cells turn against you, and the treatments are as brutal as the sickness.
Christopher Hitchens was one of the best writers of our time. Whatever you thought of his politics and lack of religion, you had to appreciate his eloquence. Mortality is his unfinished cancer book. In another bit of irrationality I have tended to avoid cancer books as if cancer were a memetic contagion that could be transmitted through print.
Despite his illness Hitchens' wit and intelligence were undiminished. There is no despair here. We should all aspire to face our mortality with such grace.