My husband has high blood pressure at dr visits. Hbp runs in his fam. Dr never gives anything for it... If left untreated is this not dangerous?

Hypertension. White coat hypertension which appears only in the doctors office and not in the patient's life otherwise, does not appear to be problematic. We do check to be sure it doesn't turn into fixed hypertension but most often that isn't the case.
Blood pressure. Should check blood pressure at other places to see if it is high there or just "white coat hypertension". Most people's BP is better outside of the office. If the pressure is normal at home then meds may not be needed.