Diebatic foot

Greetings,
My father is diebatic i just found this on the bottom of his right foot under toe area.
I want to confirm whether it is gangrene or not?
He is diabetic for the last 30 years and have severe neuropathy also. But his sugar is controlled.
For those who are wondering why not go to doctor, i have booked an appointment with surgeon but it is 2 days after. Cant find one before.
I would be really grateful to have an answer.