In November 2014, thirteen members of the Biden family gathered for their traditional Thanksgiving celebration. But this year felt different from previous. Joe and Jill Biden's eldest son, Beau, had been diagnosed with a malignant brain tumour fifteen months earlier, and his survival was uncertain. 'Promise me, Dad,' Beau had told his father. 'Give me your word that no matter what happens, you’re going to be all right.' Joe Biden gave him his word.