Hi, First of all hypertension and diabetes, both are a high-risk factor for developing chronic kidney disease / diabetic nephropathy. As you provided information in question that your friend is on medication but the most important thing is medication helps control blood pressure and diabetes. For diabetes, you need to check his HbA1C level give you detail information or average blood sugar levels of the last few months. His doctor I think did serum urea and creatinine to check his kidney status which must be dearranged. If you really want to know the cause exactly need to further investigate to check the actual cause. There are other conditions as well which cause kidney disease which is reversible but I can only be check after an investigation which is many and should be checked according to patient history and examinations. In your case I need to know if your friend is diabetic and hypertensive from years then hypertension and DM is the prior cause of kidney disease then other which should be checked first. Hope I have answered your query. Let me know if I can assist you further. Take care Regards, Dr Waqqas Shaheen, General & Family Physician