Blood pressure for 180/150 is very high and it needs to be controlled immediately.
Amlodenk 10 mg is amilodipine 10 mg may not be enough to control this much of blood pressure.
He may be needing some other additional drugs to control his blood pressure.
You havnt given the BP 2 days ago.
To decrease the blood pressure immediately the oral drug usually prescribed is atenolol
50 -100 mg for very high BP
The dosage depends on age, weight and many other factors. which your doctor may be knowing.
It is highly advisable to get him to a doctor who may analyse his blood report and prescribe some other alternate drugs.