According to the John Carreyrou book, not so much her parents, but an early and enthusiastic sponsorship from an influential Stanford professor, combined with a truly outlier ability to network with and impress powerful people. She accumulated an amazing amount of social proof, which she used to stockpile more social proof, ad infinitum.
Didn’t Carryrou’s WSJ stories say that her parents’ govt connections pulled in Schultz and got her connected to the military? I remember his reporting implying that a lot of the money Theranos raised seemed like it came in expecting military applications and thus military contracts. Which the military board (that her parents connected her with initially) would have helped with.
I believe that Carreyrou's book says Holmes built a relationship with George Shultz, then Henry Kissinger, William Perry, and Sam Nunn, through Stanford's Hoover Institution. They were all fellows at Hoover. I'm looking at page 181 in the hardcover edition. The book doesn't mention any family connections to Shultz. The military interest originally came from James Mattis, then head of US Central Command. The book says that Holmes met him "at the Marines' Memorial Club in San Francisco," but doesn't say more about that first meeting.