Malik Obama told The Associated Press on Sunday that the family sees no reason why Obama shouldn't be elected for a second term.
He was speaking during a sports tournament that he organizes every year in honor of their late father, Barack Obama, Senior.
Villagers at Obama's father's home town of Kogelo have high expectations that Obama will win. At the St Richard Catholic church, Okech Ogombe, 53, a church elder, said he prayed for Obama's re-election.
Most Kenyans consider Obama, the son of a white mother from Kansas and a black father from Kenya, as one of their own. Barack Obama has five Kenyan half-brothers and a half-sister.