Andrea saw the concerned looks on the faces of the other Celtics. She saw the stretcher wheeled onto the court. She saw her son immobilized and taken away, and she felt as helpless as any mother would. “It was awful,” she said by phone on Sunday. “If I could’ve jumped through that TV, I would have. I felt like he was halfway around the world.” Andrea was relieved by each bit of news she received as time passed. And on Sunday, Kemba was actually on the court with the Celtics after the practice was opened to the media.