doctoring

Question:  Should doctors listen to patients desire for treatment when at odds with the patient? For example, I want the doctor to let my mother have her regular thyroid extract back rather than lowering it just because the so called test indicated it could be high.  I know from experience that just going on test results does not give the whole picture.  Mother's symptoms and actions show that she is going more low than should be, but doctor is in disagreement with me just because he says tests show she is a little high, and at moment demands to leave it there or we can get another doctor.  Hopefully this matter will change when we discuss it further this p.m.  But just where does a person stand when dealing with doctors for their mother who ask verbally to care for her needs of health and medical care, when she is near ninety five and cannot be accountable to make  proper decision's?  Joylee