Your DN is a bit .... erm .... rubbish tbh. You may find it easier like this, when non Diabetics eat a normal meal of lets say fish, chips and mushy peas the carbs in that meal are turned into glucose and they then produce insulin to get the glucose into the cells in the blood stream. They will spike a little but return to pre chip butty levels fairly quickly and easily. When those of us with insulin resistance eat the same meal we spike higher and longer because the glucose cannot get into the cells as efficiently, it sticks onto the outside of the cell like stalker at your window. This is called glycation and is what is measured when you have a HbA1c. Our livers don't help much and our pancreas's load our bloodstream with insulin to try to force the glucose into the cells. This is not a good thing because too much insulin can be harmful, too.
Classic signs of Type 2 Diabetes are fatigue (because not enough energy is being had by the cells), excess urination (because your body trys desperately to try to get rid of excess glucose) and peeing which is a result of trying to sate the thirst and in tandem with the kidneys to try and rid the body of that excess glucose.
And finally, you are not a clone of your Dad. We all react differently and have different levels of insulin resistance or carb intolerance and we all store excess carbs as fat either around the waistline or the organs or both.