I'm not at all convinced, based on what we were shown in OotP, that Sirius ever really confused James and Harry. He was frequently accused of confusing him, but did we actually see him do it? The most we got was that one argument when Sirius says "you're not as much like your father as I thought." Which was a mean and unfair thing to say, but doesn't exactly show an inability to tell the two apart, does it?
I think the problem is not that Sirius can't tell James and Harry apart, but that there's a whole lot of stuff Sirius just doesn't know about Harry, and he fills the gaps in his knowledge with what he knows of James. Which isn't that unusual; I know that many of my mother's friends expect me to act like my mother, and these are people who've spent a lot more time with me than Sirius has spent with Harry. I bet when my friends' kids grow up, I'll be falling into the same trap, too. :-)
In Sirius' case, the situation is made worse by the fact that the years he spent strutting around Hogwarts with James were probably the best years of his life, and he wants to recapture them. I think Hermione had a good point when she suggested that Sirius was trying to live vicariously through Harry.
no subject
I think the problem is not that Sirius can't tell James and Harry apart, but that there's a whole lot of stuff Sirius just doesn't know about Harry, and he fills the gaps in his knowledge with what he knows of James. Which isn't that unusual; I know that many of my mother's friends expect me to act like my mother, and these are people who've spent a lot more time with me than Sirius has spent with Harry. I bet when my friends' kids grow up, I'll be falling into the same trap, too. :-)
In Sirius' case, the situation is made worse by the fact that the years he spent strutting around Hogwarts with James were probably the best years of his life, and he wants to recapture them. I think Hermione had a good point when she suggested that Sirius was trying to live vicariously through Harry.