Fixing America's Marred Immigration Laws to Improve and Ensure Security or the FAMILIES Act This bill requires the Department of Homeland Security (DHS) to inspect the conditions of family detention centers. It also requires reporting to the congressional homeland security committees on family separation, care of unaccompanied alien children, and alternatives to detention. DHS must (1) submit to Congress a maritime border threat analysis describing current and potential terrorism threats and improvements needed at U.S. sea ports, (2) develop a plan for managing its border security technology program, (3) provide for an option under the Secure Mail Initiative to have the U.S. Postal Service use the hold for pickup service or the signature confirmation service in delivering a document, (4) revise standards the hiring and retention of border patrol agents, and (5) provide for the care of alien children under the age of 18 who are in detention.