Oliver Jack Carter Lomas-Davis, known by many as "Bernie Baby," was just four months old when he died on February 25, his aunt Anastasia Lomas told The Associated Press.
Little Oliver became an internet sensation after his mother, Susan Lomas, posted photos on Facebook and Twitter of him meeting the Democratic presidential hopeful at a political rally in Las Vegas.
Sanders appeared overjoyed to see the tot in a white-haired wig, oversized glasses, little plaid tie and nametag "Bernie," the candidate’s logo.
Sanders smiled as he picked Oliver up and held him, while the pint-sized doppelganger grinned back.
“Happiest baby ever! Tragically taken by SIDS,” Anastasia Lomas wrote on a GoFundMe page created to offset funeral and counseling expenses.
More than $22,000 had been raised in five days, as mourners offered their condolences and prayers to Oliver’s family.
“Prayers for you and your Angel Oliver,” one donor wrote.
“No words can lessen or describe the pain you must feel inside. May the little baby’s soul rest in peace. I’m so sorry,” another person wrote.
Sanders spokesman Michael Briggs told the AP that the candidate had been told of Oliver’s passing and the campaign planned to issue a statement.
“It’s very sad,” Briggs said.
The baby’s mother took to social media to express her sorrow, writing on Facebook: “I love you dearly, I love you most. I love you with all my heart and soul. I know that God will keep you near since God and truth are here.”
Funeral services are scheduled for 12:30 p.m. Tuesday at Forest Lawn Hollywood Hills Church of the Hills.