My Dad Has Had His Leg Amputated Die To Gaseous

My dad has had his leg amputated die to gaseous gangrene. He's had 4 ops in 5 days and wasn't woken in between. He has now been in a coma for nearly 2 weeks. He is not connected to any machines and is breathing for himself and coughing, swallowing and yawning, he just won't respond to anything. His sugars weren't stabilised before the first lot of surgery, is it possible he is in a diabetic coma?