You say that like it was a bad thing. What's wrong with one less family member of a tyrannical, despotic regime.
Because the reason that person, family member or not, was executed was because he was a risk to the despot. If he was a risk to the despot, then from our point of view, it would have been good to have him around.
The pattern is the same for nearly every tyrannical personality who acquires power. Stain, Mao, Pol Pot, the list is long and old.
What puzzles me is how despots keep their killers so loyal to them.