If his sight is bad maybe suggest an eye check up to see if he passes that?
The DMV office has the vision check machines.

But then if he fails there, I don't know if they make him turn in his license then or not.. until he can pass the test... could be a good way to do it unless he will get very upset if his lic is taken.

Or get a test with his regular eye dr?

He could injure or kill someone or cause lots of property damage and lose everything he has....

Does he actually drive much at all??
or maybe it's just reassuring for him to have the car there in case of emergency??