WHY DO YOU THINK THAT HELPED YOU? I would not discourage or oppose the patients cultural beliefs. If they believe that the cure is helping than there is no harm in letting them maintain their positive outlook. I would look at approaching the situation by dealing with it in terms of having secondary or alternate options. By educating them on what ails them and encourage the treatment as a precautionary and alternative solution. As a plan B to ensure success.
If I was to tell them that their notions were unrealistic than I would surely push them away.