None taken here...but I would assume so, but I guess it all depends on how he had that set up. I've heard of families having to sue over royalties and that would be hellish to do after losing some one so dear.
This is Jack we're talking about. A very forward thinking individual. I'm pretty confident he had even a blanket Will (or updated one) after he released his book. Usually only time things go to appeal court is if there's no-will or things aren't declared outright or too many stipulations.
I'm not a lawyer I just stayed at a Holiday Inn.
RHP