I have told him he can’t drive anymore. He accused me of keeping him jailed, even though I have said I would drive him in my car anywhere he wants to go. I already drive him to doctor’s visits. I won’t be in a car if he is driving. He barely shuffles around the house, so I know his reaction time behind the wheel would be slow. At the moment the battery is dead.
If you don't fully understand your POA and hour with an elder law attorney will help you in understanding the rights and obligations therein.
So for now, best to keep the battery dead, along with any other disabling to it that can be done, and of course hiding the keys.
And of course ask his doctor to write a letter not only to your husband but also the DMV stating that he can no longer drive.
You do NOT want your husband killing some innocent child/person because of him driving with a broken brain.
It is no different than someone driving drunk or high on drugs, and you would never be able to live with yourself if he were to do that and you allowed him to drive.
So do whatever you have to at this point to keep everyone safe on the road ways.