Sen. Bernie Sanders‘ family is in mourning after his daughter-in-law, Dr. Rainè Riggs, died over the weekend. She was 46.

The mother of three had been diagnosed with neuroendocrine cancer two days earlier, according to her obituary from the Lee & Martin Funeral Home in Burgettstown, Pennsylvania.

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The family said that Riggs, who was married to Sanders’ son, Levi, had fallen ill three weeks ago but her condition left doctors “stumped.”

It wasn’t until last week that she returned home to the University of Pittsburgh Medical Center, where she learned of her cancer diagnosis.

“How can the world ever be the same when it said goodbye to such a beautiful soul? It is simple…. our world will never be the same,” the family wrote of Riggs, who they said earned her doctorate in neuropsychology at the University of Vermont and spent her life dedicated to medicine and psychology.

Image zoom Rainè Riggs Courtesy Riggs family

“I don’t know how our family will ever get over this loss as she was loved so much. I do know that we will continue on because we have to…. we promised her we would,” the family continued.

“We promised to love her children every day as if they were our own,” the family went on, referencing her three kids with Levi, Sunnee Riggs Sanders, Ryleigh Riggs Sanders, and Grayson Riggs Sanders.

“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,” they added. “Rainè Riggs, we will miss you every day until the day we see your beautiful smile… I know you will be waiting for us.”

Representatives for Sen. Sanders did not immediately respond to PEOPLE’s request for comment.

Image zoom Sen. Bernie Sanders Paras Griffin/WireImage

Riggs’ passing comes after a particularly difficult time for the Sanders family.

Last Tuesday night, the presidential candidate, 78, was admitted to a Nevada hospital and had two stents inserted after having a heart attack while on the campaign trail.

“I want to thank the doctors, nurses, and staff at the Desert Springs Hospital Medical Center for the excellent care that they provided,” Sanders said in a statement on Twitter last Friday. “After two and a half days in the hospital, I feel great, and after taking a short time off, I look forward to getting back to work.”

He later shared a video of himself with his wife, Jane O’Meara Sanders, in which they both thanked everyone who sent their well-wishes.

“Hello everybody! We’re in Las Vegas. I just got out of the hospital a few hours ago, and I’m feeling so much better,” the senator said in the video, with his arm around Jane. “I just want to thank all of you for the love and warm wishes that you sent to me.”

“See you soon on the campaign trail,” he added.