A. Nelson Mandela deserves to be called a hero because he helped abolish the apartheid system as well as reconcile the races residing within South Africa. He was awarded a nobel peace prize due to his efforts in dissolving the racial barriers during his first term as president in 1994.
Reference: "The Nobel Peace Prize 1993 - Presentation Speech"
B. In his valiant attemps to overthrow the racist government which greatly favors the white majority, Mandela was arrested and detained for 27 years. Due to the fear of a possible racial war which will put South Africa into chaos, Mandela was released by President F. W. De Klerk which became his political ally.
Reference Commonwealth Observer Group and Secretariat, (1999). National and Provincial elections in South Africa. 2nd June 1999.
He was a known philanthropist and founded the Nelson Mandela Foundation which promoted justice and equality. His foundation was also notable for it's effort in combating aids by raising awareness against the disease, assisting children and families affected by aids, and requesting the government to increase the number of antiretroviral treatment centers because he saw the potential of the drug and it's ability to fight HIV AIDS
Reference: Three Ways Nelson Mandela Fought AIDS - Candace Y.A. Montague