thats largely a myth,like many others created to excuse their behavior. In reality even generals who were absolutly loathed by hitler because they constantly argued against him at most destroyed their carriere,and even then not always permanently. you really had to go into "part of assasination plot,or at least somewhat connected" to risk your own life,let alone that of your family.
Rommel was told his family would suffer even before he was convicted.
https://en.wikipedia.org/wiki/Sippenhaft#Nazi_Germany