Bernie Sanders' Daughter-in-Law's Family 'Just Trying Every Day to Get Through' After Her Sudden Death from Cancer

Rainè Riggs was still alive a week ago.

A month ago, she had no idea something was killing her.

Now, in the wake of her death on Saturday just two days after learning she had cancer, loved ones of the daughter-in-law of Sen. Bernie Sanders are left to remember how she changed the world — and mourn her absence from it.

It’s a grieving process the family is keeping to themselves, as Riggs, 46, would have wanted.

“My sister was a very private person,” her sister Renee tells PEOPLE, “so we are keeping with her wishes and just trying every day to get through this and do the best we can.”

In an obituary announcing her death, Riggs’ family — with bruised but tender hearts — sketched her full life: the years of academic accomplishments in medicine, with a doctorate in neuropsychology; the husband, Levi Sanders, whom she met while she was working at a food shelter; their three kids together, Grayson, Ryleigh and Sunnee, who were her “crowning achievement”; and her final moments.

RELATED: Before She Died, Bernie Sanders’ Daughter-in-Law Told Her 3 Kids ‘She Was So Sorry That She Got Sick’

“Her last words were to tell her children how much she loved them and she was so sorry that she got sick,” her family wrote in her obituary. “Her last moment was spent with her No. 1 cheerleader, her mother, holding her hand and whispering in her ear how much she loved her.”

Two days after doctors confirmed Riggs had neuroendocrine cancer, she died.

Rainè Riggs | Courtesy Riggs family
Rainè Riggs | Courtesy Riggs family
Sen. Bernie Sanders | Paras Griffin/WireImage
Sen. Bernie Sanders | Paras Griffin/WireImage

“How do you go on day by day when your heart just keeps breaking over and over? How do you get out of bed in the morning when every breath you take is so painful you just want to cover your head with your blanket and hide away from the world?” her family wrote. “How can the laughter and smiles of three children heal your heart while at the same time you are crying? How can the world ever be the same when it said goodbye to such a beautiful soul?”

But Riggs’ family would not drown in the depth of their grief, they wrote.

“We will continue on because we have to…. we promised her we would,” they wrote. “We promised to love her children everyday as if they were our own. We promised to take them on great adventures, to take as many pictures as we could, to live every day as if it were the last, to share in their heartaches and celebrate their achievements. We promised this to her and so we will do it and hopefully every day the pain will become a little less. It is what she wanted.”

According to her obituary, Riggs did not want any public visitation or memorial. Her family said donations could be made to Love Without Boundaries, which provides medical care and other aid for children in need in parts of Africa and Asia. It was, her family wrote, “the charity that meant the most to her.”

Love Without Boundaries CEO Amy Eldridge tells PEOPLE “it was clear she [Riggs] had a heart for vulnerable children.”

“I think it was because she was a wonderful mom and because of her children,” Eldridge says. “She wanted to make sure as many children as possible around the world had that same chance to know love and find families of their own.”