She noted that she had not commented when asked her thoughts in the past year because it felt inappropriate—both in her government position as U.S. ambassador to Australia and as a family member from “a close generation of 28 cousins who have been through a lot together.”

But now that Bobby, as she refers to him, has been nominated to “a position that would put him in charge of the health of the American people,” Caroline wrote in a letter to senators, “I feel an obligation to speak out.”

The letter from RFK Jr.’s first cousin was addressed to those who lead committees set to review his nomination: Sen. Mike Crapo (R-Idaho), Sen. Ron Wyden (D-Ore.), Sen. Bill Cassidy (R-La.), and Sen. Bernie Sanders (I-Vt.).

She can also be seen reading the letter aloud in a video posted to X by her son Jack Schlossberg.

Ambassador Caroline Kennedy’s statement to the US Senate on RFKJr’s nomination for HHS Secretary

This is a reading of a letter she just sent to Senate Committee on Health, Education, Labor and Pensions

I’m so proud of my courageous mother, who’s lived a life of dignity,… pic.twitter.com/feysNA0Wwp

— Jack Schlossberg (@JBKSchlossberg) January 28, 2025

It expanded on—and expounded upon—issues she had raised in November, when she publicly broke with RFK Jr., calling his ideas on vaccines “dangerous.”

In her latest missive, the daughter of the late John F. Kennedy says the nominee is “unqualified” because he “lacks any relevant government, financial, management, or medical experience.” Further, she notes, “His views on vaccines are dangerous and willfully misinformed,” adding that those facts alone “should be disqualifying.” But it’s his “personal qualities,” she goes on to say, which, for her, “pose even greater concern.”

She says she has known her cousin her whole life, owing to the fact that they grew up together, and then paints a damning picture.

“It’s no surprise that he keeps birds of prey as pets because he himself is a predator,” she writes. “He has always been charismatic—able to attract others through the strength of his personality, willingness to take risks and break the rules.” This was particularly the case when it came to drugs, she goes on to say—as well as an odd indifference to animals, an issue that reared its head in August, with the bizarre tale of the environmental lawyer leaving a dead bear in Central Park as a prank.

“I watched his younger brothers and cousins follow him down the path of drug addiction. His basement, his garage, and his dorm room were the centers of the action where drugs were available, and he enjoyed showing off how he put baby chickens and mice in the blender to feed his hawks,” she writes. “It was often a perverse scene of despair and violence.”

Of course, Caroline admits, “people can grow and change.” She writes that she admires “the discipline” it took for him to “pull himself out of illness and disease” through both “his own strength” and “the many second chances he was given by people who felt sorry for the boy who had lost his father.”

Still, he “encouraged” siblings and cousins down the path of drug abuse, she writes, causing them to suffer “addiction, illness, and death while Bobby has gone on to misrepresent, lie, and cheat his way through life.”

She paints her cousin as a hypocrite on many fronts. “Today, while he may encourage a younger generation to attend AA meetings, Bobby is addicted to attention and power,” she says. “Bobby preys on the desperation of parents of sick children—vaccinating his own children,” who are now adults ranging from 23 to 40, “while building a following by hypocritically discouraging other parents from vaccinating theirs.”

The ardent supporter of the HPV vaccine added, “Even before he fills this job, his constant denigration of our health care system and the conspiratorial half-truths he has told about vaccines, including in connection with Samoa’s deadly 2019 measles outbreak, have cost lives.”

She goes on to talk about how his crusade against vaccines has benefited him. “His ethics report makes clear that he will keep his financial stake in a lawsuit against an HPV vaccine,” she writes. “In other words, he is willing to enrich himself by denying access to a vaccine that can prevent almost all forms of cervical cancer and which has been safely administered to millions of boys and girls.” 

She adds that while working on the QUAD Cancer Moonshot in Australia, she learned that “cervical cancer is among the top three forms of cancer among women in a majority of countries,” and that each year, “more than 200,000 children lose their mothers, orphaned due to lack of vaccines and screening. Those are the real-world consequences of Bobby’s irresponsible beliefs.”

Finally, Caroline admits that speaking out against her cousin was a painful decision. “We are a close family and none of this is easy to say,” she notes. “It also wasn’t easy to remain silent last year when Bobby expropriated my father’s image and distorted President Kennedy’s legacy to advance his own failed presidential campaign—and then groveled to Donald Trump for a job. Bobby,” she goes on to say, “continues to grandstand off my father’s assassination, and that of his own father. It is incomprehensible that someone who is willing to exploit their own painful family tragedies for publicity would be in charge of American life-and-death situations.”

While she goes on to say that she tries not to speak for her father—“unlike Bobby”—she is “certain that he and my uncle Bobby, who gave their lives in public service, and my uncle Teddy, who devoted his Senate career to improving health care, would be disgusted.”

She calls the American health care system, despite its flaws, “the envy of the world,” and says its doctors, nurses, researchers, scientists, and caregivers “deserve a knowledgeable leader who is committed to evidence and excellence” and “a stable, moral, and ethical person at the helm of this crucial agency.”

Caroline ends with a final plea: “They deserve better than Bobby Kennedy—and so do the rest of us. I urge the Senate to reject his nomination.”

Fortune reached out to Robert F. Kennedy Jr. for comment and will update this post if there is a response.

More on RFK Jr:

• Cardiologist and cohort of RFK Jr. warns Americans to avoid foods with 5 or more ingredients. Here’s why
• Raw milk, touted by RFK Jr. and costing up to $21 a gallon, is under fire because of bird flu. What science says about the benefits and risks
• The new fluoride study dividing the public health world as RFK Jr. calls for a ban on adding it to water