Madikizela-Mandela offered her assistance after reading that the family of Johan Meyer was too poor to travel to Cape Town from Johannesburg to fetch their son's body.
She has since been in touch with Meyer's friends, who have established a relief fund.
Meyer was one of nine victims of the attack on Sizzlers massage parlour, at 7 Graham Road, Sea Point.
Ten men were shot in the head. Most of them had their throats slit as well in the attack early on January 20.
One man in his early 20s survived and is being treated in Groote Schuur Hospital.
Clayton Wakeford of the ANC Sea Point branch praised Madikizela-Mandela for her compassion.
"Times of tragedy and reflection such as caused by the murder of the Graham Road nine need selfless and sincere actions.
"May the lives of these young, poor, white, gay men not be in vain, but teach us all to care no matter what our differences," said Wakeford.