Speak with an attorney specializing in elder law: you may have to seek to have your mother declared incompetent (due to age and/or drug dependency) and have yourself appointed guardian in order to have legal rights to intervene.Note that even without a legal right to interevene, you can contact her doctor and disclose the situation and your concerns: doctor-patient confidentiality means the doctor cannot disclose medical facts, etc. to you, but it does not mean that you cannot disclose concerns to the doctor who, if he/she is responsible, should take them into account in treatment (assuming he/she can verify them by examination, discussion with your mother, review of her pill usage, etc.).