Behind the controls of a hulking John Deere excavator, Nicholas Esposito clutched the lever, navigated the bucket claw into a mountain of dirt, and emptied it into a dump truck. And he did it like a boss, which was exactly the role the 4-year-old assumed Friday afternoon at EDA Contractors in Bensalem. Wearing a hard hat, orange vest and a fully stocked tool belt around his tiny waist, Nicholas was the big guy on the job. Or, as owner of EDA Contractors Ed DeAngelis called him, the CEO. Clearing a tear from beneath her eye and leaning into her husband's shoulder, Dana Esposito soaked in a moment that her son dreamed about his entire young life, but especially in the last two years as he battled a neuroblastoma, a rare form of cancer that took away his ability to walk for a while and nearly ended his life.