Hi... infected wound has to be drained and debrided ( cleaned ) and once all infected parts are removed either it can be sutured immediately or can be done at later stages. I suppose the scalp wound of your mother was infected, that is why its cleaned and left open to drain any remaining debris(dead tissue) for the region. But open wound in a diabetic is always a problem. Things to do: 1)Keep the wound clean and dry, watch for any pus discharge/fever. 2)Do regular dressings. 3)More importantly control the sugar levels ( i suppose the infection flared due to uncontrolled sugars). 4) take the prescribed antibiotics regularly, do not stop unless advised to. 5) antibiotics should be given according to the pus culture/sensitivity. 5) good hydration and nutrition is also important as healing is delayed in diabetics. note: i would recommend to be careful as scalp infection can spread fast especially with co-morbid condition like diabetes.