Legally, she is indeed his granddaughter. She was adopted by one of his sons.
Of course, Buffett’s troubles with his children are a whole other article. His whole “homespun salt-of-the-earth” schtick is just for public relations. What Warren wants, Warren gets.
Interesting point. I think Warren Buffett is the only self-made wealthy man, other than those in sports and entertainment, who gets only very positive coverage throughout the MSM.