The elder Nwachukwu left his native Nigeria to attend college in the United States .
At 25 , Nwachukwu has spent almost half his life living without his father , who died of leukemia when Chima was 13 .
The elder Nwachukwu left Nwachukwu 's native Nigeria to attend college in the United States .
At 25 , Nwachukwu has spent almost half his life living without his father , who died of leukemia when Chima was 13 .