If the patient localizes and withdrawals from pain there is consciousness there......whether or not they are "locked in" or in a persistent vegetative state is of not value as they are having pain that should be treated.
I would go to risk management/ethics/manager/chief of the department of surgery and/or your department for this lack of treatment of this patient....... for if there really is a "valid" reason there are no pain meds being given the staff needs to know so you can in all good conscience comply with the plan of care.