Caroline Kennedy on Tuesday warned that her cousin Robert F. Kennedy Jr. is a “predator” ahead of his high-profile confirmation hearings this week to be President Donald Trump’s Department of Health and Human Services secretary,

Kennedy Jr. rejected characterizations of him as an anti-vaxxer in a Senate hearing Wednesday where senators will weigh his confirmation as Health and Human Services Secretary—as his former billionaire running mate threatens to fund primary challenges against lawmakers who vote against him.

Robert F. Kennedy Jr. was confronted with a number of his baseless claims and a vexing abortion issue. But Republican senators treaded lightly.

If approved, Kennedy will control a $1.7 trillion agency that oversees food and hospital inspections, hundreds of health clinics, vaccine recommendations and health insurance for roughly half the country.

Caroline Kennedy, former U.S. ambassador and only living child of President John F. Kennedy rebuked her cousin, RFK Jr., in a letter to lawmakers.

Over many years, Kennedy has been clear about his beliefs on vaccines in dozens of interviews, podcasts and social media posts.

In a contentious confirmation hearing to be the nation’s top health official, Robert F. Kennedy Jr. struggled to answer questions about how he would reform Medicaid or Medicare, the government