Amardeep Kaleka said the FBI told him his father attacked the shooter in the lobby, resulting in a "blood struggle." A knife close to the victim's body showed blood on it, he said.
"From what we understand, he basically fought to the very end and suffered gunshot wounds while trying to take down the gunman," said Kanwardeep Singh Kaleka, Satwant's nephew.
Satwant Kaleka's wife, Satpal, hid with several other women, telling them to remain quiet during the horrific incident.
The gunman came into the kitchen and shot and wounded two women, she told CNN. "I grabbed everybody and said run, run to the pantry."
Amardeep Kaleka said his father worked hard and was an honest man.
"I would love for them (the public) to know that he lived his life with the principles that he knew and he was taught at a young age. It made him highly successful in America."
President Barack Obama signed a proclamation honoring the victims, ordering that U.S. flags be flown at half-staff at federal facilities and buildings.
Vigils were held Monday night, and one is set for Tuesday. The Sikh temple in Brookfield, northwest of Oak Creek, was to hold a candlelight vigil late Monday.
The Rev. Paul Armstrong of Oak Creek Community United Methodist Church, site of a Monday evening prayer vigil, said the diverse array of faiths in the community have an opportunity to further deepen bonds. "There's a few of us who will be calling folks together to organize some more interfaith services," he told CNN.
"Being in mission to the world is something we share," Armstrong said of his faith and the Sikh community. "Their hospitality is wonderful. That is something the Christian community is called to do."
The vigil was held outdoors, and a survivor of the temple shooting spoke, according to Armstrong.
"The focus was to express our sorrow and that all of us can be lights of the world," he said.
Navdeep Singh, a policy adviser to the Sikh American Legal Defense and Education Fund, says Sikhs believe in freedom of religion, community service and inclusiveness. At temples, or gurdwaras, where Sikhs hold services, everyone is welcome.
"You can come and be equal," he says.