Would they follow a broken, castrated man who can produce no heirs? I doubt it.
I doubt it, but I hope they at least have some lines of dialogue discussing the legality of ignoring the king's heir because he doesn't have a dick anymore.
Maybe they don't know he's alive, she told them all he was dead.
I mean yeah, but he said he would support Yara. I don't think he can do that and keep his existence a secret.