Ok, I know this is the Super Minority Opinion on this board, but why is "self-publishing it" automatically the right answer. Being a business person - as you pointed out - means making the right business decision. She's at a publisher right now. I don't know enough about the project to say that it's not something that wouldn't sell better as a Trad Published project. It could go either way.
I don't think it has anything to do with not believing in the story. It has to do with knowing what's best for your project and yourself and making sure they line up and you're happy with your decision.
*waits to have rotten tomatoes thrown at her*
I just think, as much as I love self-publishing, that it's not ALWAYS the auto-right answer for everyone and every project.