But Mr. Bo does study abroad, and American officials say he arrived in a red Ferrari last year to pick up the American ambassador to China’s daughter for a date. Classmates at Harvard say they have seen him driving around in a Porsche.

Mr. Bo has lately been staying out of public view, having changed his Facebook account to make it much more private, and he declined to answer questions last week as he left his apartment in Cambridge, Mass. Those who know him say he has been studying for final exams while coping with his parents’ troubles.

In interviews, many of his friends rejected the notion that he was a playboy or a poor student, and they described him as exceedingly generous. He is quick to pick up a bar tab, they said, and he liberally handed out tickets for the 2008 Beijing Olympics. “His concern for China and its people is deep-rooted and real,” said one friend in China who spends time with him during his frequent visits home. “He’s a big thinker. When he gets drunk, he talks about important things.”

Mr. Bo was largely shaped by his years in Britain. When he arrived, at age 12, he failed to get into Harrow, a boarding school with $45,000 annual tuition at the time. Although he told a Chinese magazine in 2009 that he spent a year studying for the Harrow entrance exam, Mr. Heywood, an old Harrovian, told friends he used his influence to land Mr. Bo a place at the school.

Mr. Bo became the first Chinese citizen at the 500-year-old institution, and by most accounts, he flourished. He took up fencing, became president of the equestrian club and developed proper English manners.

In 2006, he arrived at Oxford’s Balliol College, known for its lumbering lawn tortoises and its illustrious alumni, including Aldous Huxley, Adam Smith and Herbert Asquith, a British prime minister who once described Balliol men as having “the tranquil consciousness of an effortless superiority.”