President Joe Biden is meeting with his family at Camp David Sunday to discuss the future of his campaign following his disastrous debate performance against Donald Trump, NBC News is reporting. He and first lady Jill Biden were scheduled to join their children and grandchildren at Camp David late Saturday, several sources told the network. The trip was planned before Thursday’s debate but will take on a critical significance now following calls for Biden to quit the presidential race after his fragile, muddled behavior at the debate. While Democratic leaders have continued to publicly stand b…