Thanks for writing your query to us.
Since your dad is daibetic it is very neccessary that he keeps his blood sugar levels within normal range. If the blood sugars are high, wound healing
process can get delayed. Maintaining good hygiene is also important to prevent spread of infection. I would suggest that if there is no improvement in his wound over the leg & there is increase in the swelling than it is better that you consult doctor
again. Either your dad is not responding to the antibiotics that he is being taking or his blood sugar might have increased causing delaying the healing process. Kindly show the wound to your treating doctor.