During illness, it is usual with diabetics to reduce or stop eating and the medicines. In fact, even if he does not take the food, his Blood Glucose (BG) level increases. In turn tablets/insulin doses are be adjusted. Failing it, may develop ketones in the blood which may lead to serious condition like ketoacedosis & coma. To avoid the condition, as far as possible, try to eat food at every 2-3 hours interval. if you are unable to take regular food, drink plenty of liquids like water, buttermilk, limewater, skimmed milk, soup without cream, soda etc. If drinking liquid is not possible, consult doctor. Don't stop the medicine/insulin. The dose may be reduced if needed. Those only on tablets may require insulin during illness. Investigate for the cause of the illness and take the appropriate treatment. Take rest and keep the body warm. Monitor urine & blood sugar at every 6 hours. If urine sugar is high or the BG level is more than 250 mg%, check the urine for acetone. Change the tablets/insulin dose as per the report and doctor's advice. It is advisable to keep one person at home to assist you.
It is important to remember that if your BG level is more than 300mg%, you can't eat for two days, you are vomiting for two days, your illness is prolonged for more than two days and you develop high grade fever, consult diabetologist immediately.