Billionaire investor Warren Buffett's granddaughter-in-law Lili Buffett joined JPMorgan Chase as a wealth advisor on Monday. The 36-year-old will be focusing on foundations and philanthropy of the investment bank's clients, according to an Instagram post by a bank's senior executive. Lili, a graduate of Columbia University, married the Berkshire Hathaway CEO's grandson Howard Buffett in 2011.