As I said in a follow up post, if the DS thought McMaster JR was a threat, they would have struck at McMaster JR.
It would be foolish to do something that would turn him into a blood enemy, hell-bent on revenge. Killing his father would do it. At least it would for anyone I know.
People will often be willing to risk danger to themselves that they wouldn’t risk to others.
If the DS was threatening to take out his family members one at a time instead of killing him off, he would capitulate to protect them.
If he’s willing to turn on the DS he’s already their enemy and
I don’t think they’d care if they became his blood enemy. But to attack those closest to him could be a very effective strategy and send a warning to anyone else who may consider turning as well.
Likely they’d be thinking that one man can’t do much against a whole entrenched army or system and they could enforce their control through terror of what would happen closest to people if they chose to betray.
Anyway, I still think it could work on a lot of people.