Stop medicine for one week

In view of the pain the patient is incurring and the tiredness, the doctor wanted him to stop the trial medicine for a week. The doctor wanted to know whether the trial medicine is causing the pain to the patient.
My father went to the scan this morning as the doctor want to evaluate whether the tumor has reduce in size. The doctor will reduce the dosage to 10mg for the trial medicine next week at the review. This is the final reduction of the dosage.
My father weight has drop to 55kg. He is still getting the cough and this made him unable to have a good night sleep. Generally he is still able to eat but the intake is lesser.