Whilst it was inferred that Brody and Walker had been communicating to carry out the plan Carrie had worked out so accurately, presumably Saul had similar training, however ancient and would accept Carrie's mad rambling as carrying some merit. It seemed so obvious and whilst he thought she was at peak of her madness, he accepted her work and wall chart to nose around and find redacted missing undestroyed file on drone strike.
He has a career, but lost the love in his life through it. He feels deep love in caring way for Carrie, so whilst VP warned him off as did David, nevertheless, he saw what Carrie had manically repeated take place and he surely would insisted on Brody being searched.
Now whilst Brody killed Walker, no one found him to end of programne, nor did we see Brody regain the memory card, incriminating him.
Saul will help Carrie rehabilitate and say and do the right things to persuade, possibly with blackmail or demonstrating her lost memory, to satisfy David and VP and get her back in. No
doubt she will get numerous flashbacks,causing her to revisit Brody and his intentions. However, more behind her main work and with the same use of Virgil and methods.
Brody will become frustrated, angry and unable to maintain his calmer role as he perhaps has issues again in his family and particularly the daughter.
Just a few thoughts!