For a culturally self-aware care giver or individual, imposing your idea on others will not be an option, therefore the key to engaging a non complaint patient who has chosen the idea of trusting herbal medicine over a clinically tested one is persuasion: putting it before the patient the merit of using a prescribed,laboratory tested and a certified prescription over a non tested concoction without denigrating or belittling his belief in the traditional medicine he has chosen over the prescribed one.
Also, no coach has the right to ban you from doing something. It's not their job to tell you so, but I understand that he is only looking out for the team's best interests at heart.