Donto James told KTLA-TV, Los Angeles, the Alzheimer's diagnosis was made last year and the sepsis stemmed from a recent urinary tract infection.
He also said the 72-year-old "At Last" singer started a drug treatment program about a month ago to overcome her addiction to painkillers.
The Los Angeles Times noted Etta James has struggled with health issues in the past. She previously spent time in rehab to kick an addiction to heroin and underwent gastric bypass surgery in 2003, eventually losing 200 pounds, the newspaper said.
Swim Week Miami Beach 2014 [PHOTOS]