My father is 65 years old. He is diagnosed with parkinson disease about a year ago and is on medication of syndopa thrice a day and clonazepam tabs. Three months back he had a fall from staircase and no fractures or internal injury has taken place but now he is unable to walk properly someone has to assist him all tym. While walking he is bending forwards down nd falling. Can you pls suggest me the cause of it and medications or exercises.