Sees sights after G.I. helped him get lifesaving surgery An Afghan boy brought to the U.S. last month for a heart operation after a soldier took up his cause came to New York yesterday to sightsee and show off the boundless energy of a typical 12-year-old. "Before, I cannot walk so much," Assadullah Khan said during the whirlwind trip with his father and interpreter to meet the "nice people" who helped save his life. "Now, I walk everywhere. I can walk and run." Until last month's operation to patch a hole in his heart, Assadullah could barely walk across a...