Jack Schlossberg is reflecting on losing his sister, Tatiana Schlossberg, who died in December at age 35 after battling cancer.

Schlossberg, who’s currently running to represent New York’s 12th congressional district in the House of Representatives, recently spoke with Vanity Fair, where he discussed how he hasn’t processed his sister’s death.

“I don’t think I’ll ever process it. I don’t think I’ll ever,” he said. “The world will never be the same for me, not only since she passed away but since she was diagnosed with cancer about two years ago.”

Schlossberg added, “She was my best friend. We could finish each other’s sentences. And no one loved me or was a bigger fan of me of anyone else than my sister. So I miss her all the time. Every day I think about her. But it also really does motivate me to do everything I can with every waking moment I have, because I realize it could have just as easily been me, and I have an obligation to her, not just to myself, to make the most out of my precious life and all that I’ve been given in this life to give back to others and make sure that we can fund cures for the type of cancer that took her life and for other types of cancer.”

He went on to say that the tragedy has made him focused on making the most out of his life, especially when it comes to following in his family’s footsteps and pursuing politics.

“I think that there’s no higher calling than, than public service, and to me, I think politics is a noble profession, and one that I would be fantastic at serving this district as,” Schlossberg said. “She wanted me to win, and I intend to honor her by doing just that.”

Tatiana and Jack are two children of Caroline Kennedy and Edwin Schlossberg and the grandchildren of former President John F. Kennedy.

The news of Tatiana’s death was announced on Dec. 30 on the JFK Library Foundation’s Instagram. “Our beautiful Tatiana passed away this morning. She will always be in our hearts,“ read the post, which is signed from “George, Edwin and Josephine Moran, Ed, Caroline, Jack, Rose and Rory.”

A month before she died, Tatiana revealed in an essay for The New Yorker that she was diagnosed with acute myeloid leukemia, which was discovered during her daughter’s birth in May 2024. Her treatments involved months of chemotherapy and a bone-marrow transplant. Her sister, Rose, was a match for a stem cell transplant. While the cancer went into remission, it later relapsed.

“My brother was a half-match, but he still asked every doctor if maybe a half-match was better, just in case,” Tatiana wrote.

“My parents and my brother and sister, too, have been raising my children and sitting in my various hospital rooms almost every day for the last year and a half,” she continued. “They have held my hand unflinchingly while I have suffered, trying not to show their pain and sadness in order to protect me from it. This has been a great gift, even though I feel their pain every day.”

Tatiana graduated from Yale University and the University of Oxford. Throughout her career, she worked as an environmental journalist, writing for publications such as The New York Times, The Atlantic, The Washington Post, Vanity Fair and Bloomberg. She also wrote the book, Inconspicuous Consumption: The Environmental Impact You Don’t Know You Have.