Winnie Madikizela-Mandela is recovering in hospital after a minor knee operation, her spokesperson said.
"When I visited her, she was sitting up and talking," Victor Dlamini told News24 on Friday.
"Mrs Madikizela-Mandela will be kept at the hospital for the next two weeks to ensure that she has adequate rest and her progress can be monitored closely," he said in a statement on Thursday night.
"The family will keep the public informed of any developments."
The anti-apartheid struggle veteran was admitted on Tuesday evening and her doctor pronounced the minor surgery a success.
Dlamini said that when he visited her on Thursday afternoon she was in high spirits.
"In our conversation, [she] said her health problems go back to her time when she was banished to Brandfort by the apartheid government and during this period her knee first gave her trouble."
Madikizela-Mandela, a fierce opponent of the apartheid government, was banished to the remote Free State town by the apartheid authorities for her political activities.
She was also married to former president Nelson Mandela and actively campaigned for his release from Robben Island when he was incarcerated, to the anger of the authorities at the time.
"We chatted about many things and [she] also added that she was looking forward to the ANC conference in December," he said.