JOHANNESBURG (AP) -- As millions of South African students return to school after the holidays, 10-year-old Tumi Tlebjane is making the journey for the first time. On Wednesday, he started studies at a Johannesburg school for students with special learning needs. His grandmother, 64-year-old Helen Tlebjane, helped him prepare at Nkosi's Haven, a shelter that cares for people affected by HIV and AIDS. South Africa leads the world in HIV infections and is estimated to have well over one million AIDS orphans. Helen became Tumi's guardian after his mother died when he was 5. The boy has lung and heart ailments and is half the size of most children his age. He set off in the smallest uniform available for school, where he will learn life skills, music, drama and more.