Ok, maybe I should clarify. You cannot wish to live, you are going to die, that is inevitable, and you're on your death bed already in this situation. Not only that, think of this wish as something that has to be carried out by others, like a dying wish you ask someone to do for you. It is NOT a wish fro ma genie or some magical being, so instantly gaining all the knowledge before you die would be impossible, however, you could wish to know one specific thing, like, does god exist.