Hello there, I can understand your concern regarding your brother s health. But right now he is in denial and it may be very difficult to make him go to the hospital which he ideally should with such high sugars. My advice is to make him drink lots of water till the insulin acts and also try to convince him to increase his insulin doses by 2-4 units at least from the usual dose. There is not too much one can do if the patient is unwilling but be calm yourself and try to reason with him without getting into a fight. Do try to tell him that he may go into a coma if sugars continue to go higher. I do not know his age but adults are sometimes prone to diabetic coma or even brain damage due to very high sugars. But the key here is to keep him hydrated which can prevent complications till he agrees to come to the hospital. Hope this helps. Take care.