Thanks for posting your query.
Normal blood sugar fasting is Diabetes
is labeled when fasting blood sugar is > 126 mg% & postprandial blood sugar is > 200 mg%.
Your father's fasting blood sugar is > 126 mg% while postprandial blood sugar is
Your father has to take medication, considering his blood sugar status.
As fasting blood sugar is beyond the cut off value of diabetes, metformin
is the medicine of choice.
Although strict dietary restriction & physical activity helps in control of sugar but for better control he should take prescribed medication.
Dr. Mayank Bhargava