Robert seems like a great guy, someone who it would be a pleasure to know. This isn't necessarily apparent until the story is fully unraveled. Initially, Robert is a mysterious figure to the narrator, and therefore the reader. Some readers might expect him to be a good guy, just because the narrator doesn't trust him. Others might relate to the narrator's point of view, which looks something like this: throughout his marriage to the woman, Robert has been lurking in the background of his wife's life. It's no wonder the narrator thinks of Robert as a possibly shady figure. After all, Robert touched his wife's face when she worked for him. And then, Robert married the next woman who worked for him. All the while corresponding regularly with the narrator's wife.
For all the narrator knows, Robert could be planning to try to seduce the narrator's wife. The image of this rakish blind man contrasts with ideas we might have about recent widowers. But the narrator is still worried. The narrator's observation that Robert has "stooped shoulders, as if he carried a great weight there" (1.131) should probably deflate his fears. The idea that Robert is heavily burdened is hard to avoid. We instantly feel his grief, though the narrator seems almost oblivious.
Standard analyses of Robert paint him as a wise, mystical figure who guides the narrator to a path of new awareness. We agree, but think there is more to it. Robert also needs a guide or a friend, someone who cares enough to try to show him something he has no way of picturing – a cathedral. The story is from the narrator's point of view, so his change is more apparent. But, we do see movement in Robert as well. Surely he is still grieving, but he and the narrator have both forgotten themselves, in a sense. They are literally intoxicated, but are also in a creative and communicative zone. Maybe for the first time since his wife died, Robert has been able to completely take his mind of off his loss.
Though it's easy to reverse the roles and see the narrator as Robert's guide, we think the narrator wants us to understand that Robert is someone special, that he is the star of "Cathedral." After all, he gets a name, a rough age ("late forties" [1.30]), several professions, and specific interests. He even gets a beard, a hair style, and a "spiffy" outfit (1.30). That's more than either the narrator or his wife get in this story, though she gets a "pink robe and pink slippers" (2.6), "a juicy thigh" (2.23), and an interesting past.
Robert is unique in that he communicates creatively, and has a keen understanding of the world. This isn't to say that all blind people are like this. No more than all non-blind men are like the narrator. The important thing about Robert isn't that he's blind, but rather that he's a person who works with what he has to create the best life he can for himself.