High blood sugar even with insulin shots

Father has diabetes since 26 years..he lives very disciplin life do regular walk eat normal home made food but still he has high blood sugar. He has been taking insulin 2 times a day since 2009. But recently he has done blood test and his HBA1c came 12.5 so he visited doctor. Doctor has increased the doses and advise to keep doing walking and do random sugar test morning and evening for 15 days and come back. So 3 days have been passed. The test results are  coming as morning fasting above 200 and evening before dinner 380 (today it came 500). We are really worried. Is it possible to have high blood sugar even after insulin shots? He has no symptoms of high blood sugar like more thirst, tiredness, headache etc..nothing at all. Please any advice