>"Why keep him around then?"
As with good masterminds, Jay has been able to make everyone that matters think they will go farther with him than against him. He understood that the Captaincy wasn't something to strive for, just as HoH is not good in BB. Jay rightly sought to influence the captain rather than wear the hat.
Coming together is how Louie, Ben and Christa could get rid of Jay. The problem is that we are now in the individual part of the game. It's not at this stage that you think of forming a 3 person alliance when you think you are the leader's best ally.
Jay has delivered on his promise to keep Christa in power. Why would Christa get rid of him if it means that Louie or Ben takes the lead?
Jay gave Ben the win in the last expedition. Why would Ben get rid of him since he thinks he is part of Jay's plan?
Why would Louie get rid of him if he thought Jay had his back?
Louie, with the popularity he had gained with the women, was Jay's main adversary but Louie never even saw Jay as an enemy. He was too caught up with Joe Don at first and then Azmyth. Now, Louie realizes that Jay doesn't have his back. Problem is that Louie doesn't have enough of his women around him anymore and he should be the next gone. Louie could be Thailand's Ted, realizing too late what was the real plan.