Clancey smiles when she remembers how hard they laughed at that.
"The thought of her standing in line at the bank with a clown wig on I find so much humor in that," she says. "She'd rather laugh than loom in the darkness."
Jokes aside, everyone around Brooke knows she's dead serious.
"The thing that is useful to me about this disease is that I am lucid on my life purpose," she says. "I don't spend time wondering what that's about. If I can leverage this disease to expand how many people can use yoga as a tool, that's what I'm going to do. This is not just about health. This is about your life and what it could look like if you went nuts with your own personal courage."
In spite of her pain, Brooke believes strongly that her natural approach to healing is working. She concedes that traditional treatment is not completely out of the question for her as an "emergency room" only. She refuses to live her life on traditional CF treatments.
This is a scary decision for the people who love her. Though every member of her family says they accept her choice, it's clear they still worry about her. Because Jordan's transplant was so successful, there has been a push to get Brooke to consider one as well.
"Knowing how she feels and what she goes through every day, and seeing how my life is, I just wish she would go up there [to Stanford] and see what they have to say," says Jordan. "She might not like what she hears, but at least she'll have the information."
Her family worries that she might be pushing herself into a margin where she couldn't seek Western medical help even if she wanted to.
They might be right. According to Michelle Martinez, a nurse at the Cystic Fibrosis Center at Phoenix Children's Hospital who has not worked with the Sterlings and did not comment directly on their case, there is essentially a point of no return when it comes to lung functioning in CF patients.
"You can go for a long time and feel really healthy, but there can still be changes going on inside your lungs," she says. "Basically, what could be happening is they're decreasing their lung function and the lungs are becoming more damaged. Even though they don't feel it, it's happening on the most basic cellular level."
Walter III puts it more bluntly.
"My sister has chosen yoga," he says. "If she decided to go the other way now, I don't know if she could. It freaks me out."