JFK's grandson reveals sister Tatiana Schlossberg's last words to him before her tragic death

Jack Schlossberg — the grandson of former president John F Kennedy — has detailed the emotional last words his sister, Tatiana Schlossberg, said to him before her death in December.

In November 2025, Tatiana opened up on her Acute Myeloid Leukaemia diagnosis and detailed her cancer prognosis was terminal.

Tatiana continued to champion the importance of vaccines in a piece for The New Yorker that month, which went against her relative, Robert F Kennedy Jr, the current US Secretary of Health and Human Services, and his ant-vaccine beliefs.

She wrote: "As I spent more and more of my life under the care of doctors, nurses, and researchers striving to improve the lives of others, I watched as Bobby cut nearly a half billion dollars for research into mRNA vaccines, technology that could be used against certain cancers."

Tatiana Schlossberg died in December 2025 (Nathan Congleton/NBCU Photo Bank/NBCUniversal via Getty Images via Getty Images)

Just weeks later, Tatiana sadly passed away at the age of 35, with a post on the JFK Library Foundation's Instagram account confirming the sad news.

"Our beautiful Tatiana passed away this morning," it reads. "She will always be in our hearts."

Jack has been speaking about his sister during a recent appearance on CBS Sunday Morning, where he detailed that his sister told him to continue with his campaign to run for Congress.

"The last thing that she said to me was, ‘You better win,’” Jack revealed on the show. "No one knew me better, and I knew no one better than her.”

Speaking of growing up with Tatiana and their older sister, Rose Schlossberg, Jack added: "It’s brutal [to have two sisters]. Absolutely brutal. They don’t let you get away with anything. My style is never good enough. I’ve never gotten an answer right in my entire life.”

Despite the craziness that comes with that family situation, Jack heaped praise on her siblings, stating 'they taught me everything I know about how to be a strong person'.

During her lifetime, Tatiana was a champion of climate change action and spoke often about ways to combat the ongoing climate emergency.

"I think climate change is the biggest story in the world, and it's a story about everything," she told NBC News in 2019. "It's about science and nature, but it's also about politics and health and business. To me, looking at this as a journalist, it seemed like a really important story to tell."

"And if I could help communicate about it, that might inspire other people to get involved and work on the issue."