Ethel Kennedy, the widow of Robert F. Kennedy and a fierce human rights advocate, has died after suffering a stroke, a family member confirmed to CBS News. She was 96 years old.

She suffered a stroke in her sleep on Oct. 3, her grandson Joe Kennedy III posted on social media earlier this week. He described his "incredible grandmother" as a "strong woman who has led a remarkably fulfilling life."

In a post Thursday, he wrote, "It is with our hearts full of love that we announce the passing of our amazing grandmother, Ethel Kennedy. She died this morning from complications related to a stroke suffered last week. Along with a lifetime's work in social justice and human rights, our mother leaves behind nine children, 34 grandchildren, and 24 great-grandchildren, along with numerous nieces and nephews, all of whom love her dearly."

A matriarch of the Kennedy political dynasty, Ethel Kennedy gave birth to her 11th child, Rory, six months after her husband was assassinated in 1968 as he celebrated his victory in California's pivotal Democratic presidential primary.

In the months between her husband's death and the birth of her youngest child, she founded the Robert F. Kennedy Human Rights foundation in October 1968. The organization celebrates her husband's and others' dedication to human rights and public service by supporting programs for rights advocates around the world.

"For more than half a century, my mom has been a champion for justice, standing with human rights defenders around the globe," her daughter Kerry wrote on Facebook on April 11, her mother's 96 birthday.

Ethel Skakel Kennedy was born in Chicago in 1928 and grew up in Greenwich, Connecticut. Her father built a successful coal business, making the family wealthy. She was just 17 years old when she met her future husband, Bobby Kennedy, who was dating her sister Patricia at the time, according to the JFK Library website.

Ethel and Bobby married on June 17, 1950, at St. Mary's Catholic Church in Greenwich. Passionate about public service, the couple campaigned for Bobby's brother, John F. Kennedy, in his 1960 run for the presidency. Bobby Kennedy served as attorney general in his brother's administration.

After JFK's assassination in 1963, she continued to support Bobby as he pursued his political career. He was a leading contender for the White House when he was shot and killed by Sirhan Sirhan at the Ambassador Hotel in Los Angeles in June 1968.

After her husband's death, in addition to her work at the human rights center, Ethel Kennedy co-chaired the Coalition of Gun Control and was involved with many other human rights organizations.

President Obama honored her with the Presidential Medal of Freedom in a ceremony at the White House in 2014, where she was praised for her perseverance and generosity.

"She's gone to extraordinary lengths to build support for causes close to her heart," Obama said at the ceremony.

The family weathered additional tragedies over the years, including the deaths of two of her children — David, who died of a drug overdose in 1984, and Michael, killed in a skiing accident in 1997. In 1999, her daughter Rory's wedding was marred by tragedy when her nephew, John F. Kennedy Jr. and his wife, Carolyn, died in a plane crash en route to the Cape Cod wedding.