Since his fasting glucose level and
post prandial glucose level is very high , immediate priority is bring the glucose level lower by using insulin
Ideally diabetologist/endocrinologist consultation is advised
Next Steps
get his renal function tests ,
HBA1C , lipids ,
liver function tests,
thyroid function tests and urine analysis
eyes funduscopic examination
Health Tips
strict control of his diet,less carbohydrates and exercise will definitely help