I was at the Marine Corps Recruit Depot at San Diego in the 80s, and the one thing we told the new drill instructors was to NEVER say bad things about a recruit's family. A drill instructor say almost anything to a recruit and his fellow DIs and officers would hear nothing, except for family. Almost every DI and officer did something "wrong," but that was one of the few lines that we tried never to cross.
I saw and heard a lot, but that topic was never approached in a manner to degrade the family. Now you could say something like, "Your mother would probably be so disappointed in you that you can never go home (using more colorful language of course)." The idea, is that the family is a foundational part of the country, so to tear that down is the same as disgracing the flag. If any recruit showed any emotional weakness, it was exploited in an attempt to break him- except for the family. I had a recruit that had to go on emergency leave because the recruit's father was in the hospital in very poor shape. Transportation fell apart and one of his DIs drove the recruit to the airport in the DI's personal car (against all rules). No one said a thing.
Gunnery Sergeant Hartman: Did your parents have any children that lived?
Private Gomer Pyle: Sir, yes, sir.
Gunnery Sergeant Hartman: I’ll bet they regret that. You’re so ugly you could be a modern art masterpiece.