Think of it! Not only could he not make new friends, he couldn't learn about cell phones, computers, the Internet, the moon landing, World War II, or anything from the second half of the 20th Century.
And yet, he helped scientists understand the working of the brain. Because the surgeon had cut into the hippocampus, doctors were able to learn how memories are formed and stored by the brain. And amazingly, although he could not remember doing tasks that required dexterity, such as tracing a figure while looking in a mirror, he could learn how to do them better. He had no memory of the event, but some other part of his brain learned how to do it! He also seemed to recognize his doctor, someone he saw almost everyday, in that he thought the doctor was someone he had known in high school. It was like his brain was trying to close a connection it knew it should be able to make, and it found its own way to do it.
Even if we can are one day able to duplicate the human brain's cognitive functions with artificial intelligence, it's hard to imagine we'll be able to create something that also does the myriad other tasks the brain does.