Your father's blood sugar is actually not very bad, normal unfed should be around 5, diabetic less than 10, control at about 7-8 are considered good. The medication can be Metformin (won't let the blood sugar drop too low, too low is life threatening, this medication protects the heart) and Bayerisepine (eaten with food, stops the absorption of sugar, very few side effects). Your dad is too thin right now, and actually working on his pancreatic function means exercising more, not eating less. Yes, try to eat sugar free but not no food. Watch out for complications of diabetes, get your eyes checked once a year (not your vision) and your feet checked once a year. My husband and dad both have diabetes,, dad is a doctor himself and that's how they treat it and it's well controlled now. Wish your dad good health