Graca Machel told a South African television news channel that it was painful to see her 94-year-old husband, who was hospitalised on Saturday, 'fading.'
'I mean, this spirit and this sparkle, you see that somehow it's fading,' she told eNews Central Africa. "To see him aging, it's something also which pains you. You understand and you know it has to happen', she said.
Mr Mandela's grand-daughter Ndileka told the same news channel that the anti-apartheid icon has come to accept his condition.
'He has come to accept that it's part of growing old, and it's part of humanity as such', she said.
'At some point you will dependent on someone else, he has come to embrace it'.
The pair's comments are the first official remarks by Mr Mandela's family since the former President was rushed to hospital on Saturday.
Although he has remained in hospital since then, his spokespeople have issued only bland assurances about his health, saying he is 'comfortable', 'in good hands' and said that there is 'no immediate danger to him at this stage'.
Most crucially they have not divulged why Mr Mandela had to be flown over 500 miles from his rural home to undergo the urgent medical tests.Yesterday afternoon the office of President Jacob Zuma said that Mr Mandela 'had a good night's rest. The doctors will still conduct further tests today.