We need to update our Drivers' Licensing process for the elderly

Today I watched an elderly man in a very large car drive past two DO NOT ENTER signs and a NO LEFT TURN sign to enter a very busy parking circle.  I entered the circle the correct way--at the entrance--and when he approached me head-on, he just stopped, not knowing what to do. I approached.  I signaled that he should turn around.  I waited.  He didn't move.  I waited some more.  He is about 112, so I figure I can give him a minute or two to find reverse.  He backs up about 4 feet and stops.  I wait some more.  He does nothing. 

He was in a wide spot in the circle, so I pulled up next to him, about 4 feet away.  He rolled down his window.   His wife was in the passenger seat, looking a bit horrified and wearing the most awful wig.  I said, "Sir, you drove past two ... " He interrupted me and said, "What?" in what sounded like a New York accent.

I didn't want to shout because we were surrounded by people on foot, but he left me with little choice.

I said again, pointing at the exit, "Sir, you drove past two DO NOT ENTER signs. You're going the wrong way."

He said, rather defiantly, "There's nothing there."

I said, "Yes, there is.  There are two DO NOT ENTER signs that you drove right past. And, a NO LEFT TURN sign."

Shrugging his shoulders, he said, "Well what do you want me to do?"