Thank you for posting on HCM
Let me start by answering your question. Yes the best doctor to consult for your mother's condition is a cardiologist (if available in your community) or alternatively an internist.
Your mother's symptoms: palpitation
(hearing disorder), throbbing and heaviness/weakness/fatigue
and elevated BP (malignant or severe) are all likely related to a heart condition most probably hypertensive crisis ( that is not yet under control). Some blood work and imagery such as ECG and cardiac ultrasound
would need to be conducted by the specialist to determine the cause of the problem. That will be of course after physically examining her to find out the cardiovascular signs.
Hope this helps