I will certainly question her about her reasons for choosing the path she has, but I will not attempt to force her from it, or berate her for following it. Not only do I feel I have to respect her choice of a path, but I've found that trying to fix a problem for a person doesn't work, if that person doesn't recognize that there's a problem. Even if we correctly perceive that someone is a victim, the victim has to want to be rescued, or she won't stay rescued. The way I interpret the Rede, I may interfere with another's free will only if that person's actions are causing harm to others, or if they're presenting a convincing threat of harm. The Rede permits taking action against a cult which practices human sacrifice.
Some religions disapprove of medical treatment.
The Jehovah's Witnesses, for example, forbid blood transfusions. Many Fundamentalist Christians believe that all healing comes from God, and that visiting a doctor for any reason is usurping God's domain. These people are welcome to forego medical treatment themselves, but I will do whatever I need to in order to keep them from outlawing medical treatment for people who do want it. Perhaps the best way to deal with the issue of harm is to reflect on how we would treat analogous behavior if it were not religiously motivated. A man stands on the corner screaming about how his religion is the only True Faith.