In a move expected to save three struggling Brooklyn hospitals, the Obama administration has finally agreed to let the state reinvest $8 billion in Medicaid savings into its health care system, Gov. Cuomo said Thursday. Cuomo has repeatedly warned that without the approval, Brookdale Hospital, Interfaith Medical Center and Wyckoff Heights Medical Center would soon shut down. U.S. Health and Human Services Secretary Kathleen Sebelius told Cuomo Thursday that the feds are ready to sign off on the request. The $8 billion is $2 billion less than the state had sought, but it's enough to help remake the health care system, Cuomo said.