Makaziwe Mandela, in an interview to national broadcaster SABC, said the 95-year-old world's icon continues to fight against the ailments ravaging him.
"Tata is still with us, strong, courageous. Even for a lack of a better word on his 'deathbed' he is teaching us lessons; lessons in patience, in love, lessons of tolerance. Every moment I get with him I'm amazed," Makaziwe said.
"There are times where I have to pinch myself that I come from this man who is a fighter even though you can see he is struggling, but fighting spirit is still there with him," she said on Tuesday.
Madiba (Mandela's clan name) was admitted to the Pretoria Heart Clinic in June, where he was treated for a recurring lung infection before he was released to receive home-based care nearly three months later.
At the time there was a outpouring of love and concern for the elder statesman from around the world. However on Tuesday, it was quiet outside Mandela's Houghton home, where a slew of specialist physicians are attending to his health.
Grandchild, Ndaba Mandela, has also lamented Mandela's ill state. "He is still with us although he is not doing well in bed."
Last month, Mandela's ex-wife Winnie Madikizela-Mandela said he was no longer talking "because of all the tubes that are in his mouth to clear (fluid from) the lungs".
The South African presidency has repeatedly described Mandela's condition as critical but stable.
Mandela, who spent 27 years in apartheid jail before becoming South Africa's first black leader, has faced several health scares. His most recent hospital stay spanning over three months was his longest since he walked free in 1990.
Mandela is widely respected for his role in fighting racism in South Africa, and for forgiving his former white captors after his release from prison.