Hi the question is not very informative. If a person with diabetes is having repeatedly low sugars especially at night..it's important to pay attention to that person..as to what might be the cause. This is important because if low sugar episodes are not corrected body loses its tendency to identify low sugar and doesn't warn the patient with symptoms. As per the cause..we have to evaluate dietary history, medication details and if needed few blood tests as well. Best strategy is to consult an endocrinologist to help identify the cause and take necessary precautions.

If the patient is on antidiabetic medicines, the medicines need to be changed immediately. if not the cause for this needs to be diagnosed. Consult a doctor ASAP