The daughter-in-law of Democratic presidential candidate Sen. Bernie Sanders has died at age 46, days after being diagnosed with neuroendocrine cancer.

Dr. Rainè Riggs was the wife of the Vermont senator's son Levi Sanders, 50, and mother to three children, Sunnee, Ryleigh, and Grayson. She was an accomplished neuropsychologist who once served as the co-director of Behavioral Medicine at Dartmouth Medical School and is credited with developing and launching the Palliative Care Department for Dartmouth Medical Center.

Riggs complained of feeling ill weeks ago and was diagnosed with neuroendocrine cancer following a battery of tests just last week. She died two days after her formal diagnosis on Saturday, the day Bernie Sanders, 78, returned to Vermont following a heart attack he suffered on the campaign trail.

Levi Sanders, who met Riggs while working at an emergency food shelter in Vermont, launched an unsuccessful bid for Congress representing New Hampshire in 2018 but was defeated soundly in the Democratic primary. The younger Sanders never received the endorsement of his father which many felt could have significantly buoyed his chances of victory. "Levi has spent his life in public service to low-income and working families, and I am very proud of all that he has done," Sen. Sanders said at the time. "In our family, however, we do not believe in dynastic politics. Levi is running his own campaign in his own way."

Bernie Sanders has stated that he intends to "change the nature" of his presidential campaign after his recent heart attack, noting that he should have paid more attention to the fatigue and stress he felt in his bid for the White House. He has not yet commented on the death of his daughter-in-law.

"Rainè, a truly selfless person, was always heavily involved in working with the homeless, especially homeless veterans," said an obituary for Riggs published by the Lee & Martin Funeral Home in Burgettstown, Pennsylvania. "Rainè also spent time volunteering with pediatric hospice. Rainè was the owner of Riggs Geriatric Psychology in Windsor, Vt. She also volunteered at ground zero after the tragedies of 9/11, providing much needed counseling for survivors, first responders and the families of those who lost their lives."

"I don't know how our family will ever get over this loss as she was loved so much," the obituary said. "I do know that we will continue on because we have to ... we promised her we would."

Services for Riggs will be held in private with requests that contributions in her memory be made to Love Without Boundaries, a charity for orphaned and impoverished children.