The Press-Enterprise reports that the soul singer's ill health came to light during a recent court case between her husband Artis Mills and son Donto James over an estimated $1 million set aside for her healthcare costs.
Donto has asked a judge to assign the funds to an outside party capable of making an impartial decision "to avoid present and future family conflict and discrepancies", while Mills argued that he is the only one aware of Etta's true wishes as to how the money should be spent.
"[Etta said that] if she ever became disabled, she did not wish to be placed in an institutional nursing facility as long as they had the money to keep her at home," Mills explained.
Her physician Dr Elaine James confirmed the 72-year-old's illness in court documents which said that she is suffering from "multiple medical conditions, including dementia, an organic brain syndrome and a recent diagnosis of leukaemia" and that while she is able to recognise her husband and son, she cannot sign her name and needs help with washing, dressing and feeding herself.
She is currently receiving 24-hour care at her home in California.
A hearing on the matter is scheduled for Friday.