My Dad's drivers license was taken away but he is still driving. What do I do?

Thank you very much, I have reported to the DMV, now to the local Police. He is not thinking in he's right mind anymore. I'll keep you all updated.

Oh yes, you can disable the car and lose the keys. He is a real danger to himself and those poor unsuspecting families he might run into. That thought alone would make me stop him from driving.

Do you have permanent court appointed guardianship status over your father? If not, not much you can do other than to report to your DMV and or local police that he is driving unlicensed.

OH and notify the local police in case he reports it stolen.

Borrow the car. Don't bring it back.