I've done flights for terminally ill children and I can assure you it is the pilot that reaps the true reward. Seeing a smile on a young one's face in those circumstances cannot be described adequately. If you ever get a chance to help out....do not hesitate for a second.
I flew a young teenaged boy, Leukemia sufferer, and when I asked about his status three days later, was told he had passed. Odd how one can be struck by the unfairness of life at times.