Rivera, who had previously battled cancer and had lost his older brother to the disease, announced his intention to match donations of up to $100,000 toward a cure for childhood cancer, a special cause to his late mother.
"My family has dealt with a lot of cancer, but mom would say the worst is childhood cancer," Rivera tweeted along with a photo of himself alongside his late mother. "My mom had a beautiful life and she would want a child to have the same. If you click this link & donate, I will match up to $100,000 to St Jude Hospital."
The Commanders announced Dolores' death on Tuesday (November 1) after the head coach was reported to be absent from practice due to a "personal matter" concerning his mother.
"We are saddened to announce that Coach Rivera's mother Dolores passed away peacefully yesterday evening with her husband and family members by her side," the team said in a statement shared on its verified Twitter account.
"Coach Rivera is grateful he was able to spend two days with her last week. The Snyders and the entire Commanders family extend their heartfelt condolences to Coach Rivera and his family.
"The Rivera family would like to say thank you for the many kind thoughts and prayers they have received. Arrangements are pending, and we would ask everyone to please respect the family's privacy during this difficult time."
Ron Rivera underwent his final cancer treatment at a Virginia hospital in October 2020, just hours after the Commanders' 25-3 home victory against the Dallas Cowboys.
Rivera received his last round of chemotherapy and proton therapy, which concluded seven weeks of treatment after initially announcing he was diagnosed with lymph node cancer in August 2020.
Donations to St. Jude's made in memory of Dolores Rivers can be made through the charity's website.