Treledees Almost Tells Siri How to Pass On the God King's Breath
We get to see more of Siri taking charge here. In this tense situation, a lot of others would have been reduced to hysterics, but she's come into her own, taking command, trying to get the information she needs.
Treledees lies to her here about two things. First off, he does know how a God King can have a child, but he knows that the secret is also held by a secure group of priests on the islands. He doesn't think letting Siri in on that one for now is a good idea. But he does want to pass on how to get Susebron's Breaths away from him, should it become necessary. He knows that those need to be passed on, even if the God King does have a child. That's the greater secret, but the one that needs to be known to Siri. Those Breaths cannot die with Susebron.
So, anyway, he's lying about the God King not being able to have a child. (Or at least he sidesteps it. He says that the God King can't sire a child, which is true unless certain steps are taken. He also says that he doesn't know how the First Returned bore a child, which is true—he doesn't know for certain if the First Returned used the same method that Treledees knows. He's also sidestepping the fact that he does believe that the blood of the First Returned flows in the veins of the royal Idrian line.)
So why not bring this up in the book? Well, I learned in Elantris that it's easy to overtwist an ending by having too many reveals. This is a very small point, and there is good rationalization for why Treledees doesn't let on what he knows. So I felt it was better to let the story stand as is, without delving into this.
Of course, there is a hint in the text about it—or at least a question. If they depended only on a Returned child taking Susebron's place, then why were they worried about Siri having sex with Susebron? They didn't need her to sleep with him unless they expected that sex to do something.
I'm sorry to leave this issue a mystery, and I'm even more sorry to not explain how Susebron can give away his Breaths. It's not important to this book, and so I felt that having Treledees give the explanation here would just bog things down. I'd rather wait until a sequel, where I detail the magic system in a more complete form, to give you these explanations.
That leaves us with the cliché of someone who almost passes on information, then dies. As I said, I am sorry to do this. I nearly didn't put it in, but I felt it very important to include something that let you know that the priests did have a way to get those Breaths.
Note that Treledees is not lying about letting Susebron live out his life with Siri in peace. They have allowed previous God Kings to do that, once they had a successor in place.