Speaking Sunday on NBC's "Meet the Press," Shriver said one day after her uncle's funeral and burial that Kennedy's "heart was extraordinary."
"He was the most compassionate, empathetic man," she said. "And I think he was that way because he himself was wounded and he himself knew pain, he himself knew struggle, he knew abandonment."
Shriver, whose mother and Kennedy's older sister, Eunice Kennedy Shriver, died Aug. 11, said that even though their deaths were not unexpected, "death is always a surprise. I've just gone through two in two weeks, and it's always a surprise and it's always final and it's always difficult, and I think people grieve in their own way and in their own time.
"So I think Teddy was one of those larger-than-life figures in our family, he was really the center of our family, and he was one of those people that you never expected to die," Shriver said.
'Duck Dynasty's Phil Robertson on indefinite hiatus after anti-gay remarks
Nativity scenes to be moved at Guantanamo after troops' protest