A close friend of Dana Reeve said that Reeve knew for about six weeks the end was approaching and that she died in peace late Monday.
"We kind of knew, and Dana was surrounded by family and friends," said Michael Manganello, Christopher Reeve's former assistant and vice president of the Christopher Reeve Foundation. "Dana was an elegant and graceful woman, and she left this world the same way. She was at peace."
Reeve died of lung cancer at Memorial Sloan-Kettering Cancer Center. She was 44.
She first announced in August that she had been diagnosed with lung cancer, just 10 months after her husband had died from complications related to his spinal cord injury. She told "Good Morning America" in November that the hardest part of her diagnosis was telling her 13-year-old son, Will.
"He was very young when Chris had his accident, and in a way it was almost easier because, well, partly it wasn't me. So I was able to say everything else is fine. We're going to be fine, and you know, Daddy'll be, well, it will be different, but fine," Reeve said. "I've always been his rock, and just following so quickly on the heels of his father's death and my mother's death. … It just has been a very rough year on our family."
Manganello said friends and family were helping Will with his most recent loss.
"He's going to be surrounded by so many people who love him that Will will be fine," Manganello said. "Nobody has enough time with their parents, but I think that Chris and Dana spent such a remarkable time with Will and they did such a good job raising him."
Reeve also leaves behind two stepchildren -- Alexandra, who graduated from Yale last May, and Matthew, a documentary filmmaker.
"Clearly, Dana was an incredibly smart woman, and she knew this was a very serious diagnosis," Manganello said. "But she was not ready to go and she was certainly not willing to leave her family, and that's the way she left this world -- but at peace, truly."
Reeve had succeeded her husband as chair of the foundation, which funded research into spinal cord paralysis cures.
"The world is not going to be quite as much fun for me without her in it," Manganello said. "But she left me with so much."