To understand the Saudi royal family, you don’t go to the Kennedy School of Government, you read Shakespeare!
—Bruce Riedel, former CIA national intelligence officer for the Middle East
It’s in the 2nd ‘Graph of the article linked above.
It describes the rather convoluted and dysfunctional succession politics in the House of Saud, and it’s a good read.
It appears that the current king suffers from dementia, and his two most likely successors are engaged in a death match to assume the throne.
When the House of Saud falls, and it is when, not if, it will start with a dynastic dispute, and honestly, I think that this might be the time.
Saudi family politics have always been dicey, but with the King being pretty much a figurehead, and his successors being young enough that either one would have a reign of decades, this looks to end up a complete hairball.