Hello sangtrd Welcome to Health Care Magic Erectile dysfunction or inability to achieve full erection is one of distressing complication of long standing Diabetes Mellitus. A lot of factors contribute to development of this side effect, poor control of glucose is one of them, other is associated hypertension, premorbid conditions and health status of patent. To treat the erectile dysfunction associated with diabetes a detailed evaluation of patient is needed. - Visit a good doctor along with patient and get himself evaluated for any associated hypertension or any other heart disease. If every thing comes normal then medicines as Sildenafil (Viagra), or Tadalafil (Tazzel) can be given to him, prior to sexual intercourse. - Other medicines as Trazodon (trazonil) can be taken as they will also cover the low mood part along with erectile dysfunction but only after consultation of psychiatrist. - Proper control of sugar is must. - Balanced high fibre diet is also must. - Vitamin Supplements to check nutrient deficiency if any. - If not possible with these methods go for Sex Therapy with some qualified psychiatrist and other options as Vacuum Devices can be kept in mind. Thanks Take Care