(CNN) Former White House chief of staff and retired Marine Gen. John Kelly has joined the board of directors for Caliburn International, the parent company of Comprehensive Health Services, which operates shelters for unaccompanied migrant children.

One of the shelters the company operates is Homestead, a temporary influx facility in Florida that houses unaccompanied migrant children.

"General Kelly is a strong strategic addition to our team," said James Van Dusen, the CEO of Caliburn International, in a statement.

He added: "Our board remains acutely focused on advising on the safety and welfare of unaccompanied minors who have been entrusted to our care and custody by the Department of Health and Human Services to address a very urgent need in caring for and helping to find appropriate sponsors for these unaccompanied minors."

Kelly's ties to family separations date to when he served as secretary of Homeland Security under Trump. He confirmed in 2017 that the department was considering separating children from their parents at the border.

"Yes I'm considering (that), in order to deter more movement along this terribly dangerous network," he told CNN's Wolf Blitzer at the time. "I am considering exactly that. They will be well cared for as we deal with their parents."

Kelly's successor as secretary, Kirstjen Nielsen, later faced sweeping backlash over the administration's zero-tolerance policy, which resulted in thousands of families being separated. A judge eventually blocked the program and ordered all families be reunited.

Kelly also praised HHS as doing "a very, very good job" of putting migrant children "in foster care or linking them up with parents or family members in the United States" during the 2017 interview. The Office of Refugee Resettlement, which is within HHS, is tasked with caring for migrant children who arrive at the border without a parent or guardian and placing them with a sponsor in the United States.

Democratic presidential candidate Sen. Elizabeth Warren on Friday slammed Kelly's career shift as "corruption at its absolute worst."