"My sister is being viciously attacked. And let me assure you - it is all bulls**t," he began on Facebook, before encouraging those who don't support Ellen to unfriend him on the social media site.
"I'm sick and tired of my sister being attacked," he added. "She always has - and always will - stand against bullying of any kind. She's a smart, strong woman who has made a positive difference in the world."
"And to my friends who did respond with support for Ellen and my family, thank you so much," Vance concluded. "It means a lot."
Vance also took to Twitter in his sister's defense, writing, "If you think Ellen would knowingly allow bullying or racism on her show, you don’t know my sister."
"She has been and continues to be a bright light in a dark world," he tweeted. "She’s one of the kindest, most generous people you’ll ever meet. And one of the funniest."
Last month, Warner Bros. Television sent an internal memo informing staffers that WarnerMedia would be seeking the services of an independent third-party firm to interview current and former employees about their experiences behind the scenes on The Ellen DeGeneres Show, after one current and 10 former employees anonymously spoke with BuzzFeed News about their negative experiences working on the program.
In an internal letter sent to show staff, which was obtained by ET, DeGeneres apologized and affirmed that she was committed to "having conversations about fairness and justice."
Additionally, ET learned that a virtual staff meeting was held on Monday to update show employees on the current investigation into alleged workplace misconduct.
ET has been told there are staff who feel hopeful there will be positive change on the production side of the show and more involvement from Ellen herself. New episodes of The Ellen DeGeneres Show are slated to begin filming in September.