Hi welcome to the health care magic Diabetes should be controlled with life style modification And less sugar eating with exercise also... To avoid it s complications Here he could have Renal affection secondary to diabetes leading edema, for that USG, serum urea and creatinine estimation done Also check serum protein level and cardiac condition(EKG if needed) ,to rule out hypoprotememia and cardiac causes According to cause further specific treatment given Diuretic can be prescribed for improvement Hence depending on examination further investigation planned and accordingly get your prescription Take care With keeping this in mind consult physician for examination