Given the way the company was structured, I don’t see an easy way for the sons not to know.
I personally think Ruth knew as well as Bernie’s two female helpers.
I’m not convinced the wives knew. Maybe, maybe not.
This^^^^^^^^^ and there was probably many more involved. You don't keep track of billions with just a handful of people
One of the son’s wives filed for a divorce that was orchestrated with the timing of Bernie’s arrest. But it was seen by the Feds as Kabuki and the action has been stopped by the Feds while the investigation continues.