It is hard to prognosticate the implications of this, since he was old, his successor was probably chosen long ago, and it could be anything from a non-eventful transition of power that hardly makes the news, to a civil war, to anything in-between. They say the hardest thing to predict is the future.
The hardest thing for the Saudis will be who gets to rule when the last son of the first King of Saud dies.
Do the sons of the new King get to rule? There are several hundred cousins to argue that they shouldn’t.