But Mandla's lawyer Gary Jansen said: "They relied on certain affidavits in particular with regards to the health of the president which wasn't true."
Jansen's team would therefore file a complaint with the bar council and law society, he told South Africa's Sapa news agency.
The legal team representing Mandela's relatives, including his wife Graca Machel and three daughters, had filed the document in their bid to speed up the legal process on the dispute over the burial sites of three of Mandela's children.
They eventually won the case against Mandla, who had moved the graves without the family's consent in 2011.
The document filed ten days ago said doctors had recommended switching off the former statesman's life support machine and described the 94-year-old Nobel peace laureate as "in a permanent vegetative state".
The South African presidency has since denied that Mandela is in a vegetative state, and the Nobel laureate's close friend Denis Goldberg told AFP he was conscious during a visit last Monday.