It’s easy enough to say a character should be active, driving the story forward, have a goal etc. but what if he isn’t that sort of character?
A lot of young male writers that I read and critique in the various writers’ workshops I belong to, write about young male characters who don’t know what they want, who haven’t decided what their goal is, who don't care about anything. These writers want to write a story of discovery. They want to write about how to figure out which are the important things. They want to rage against the ridiculousness of life, in no particular order.
They want to write about these things because life doesn't conveniently offer up a neat, pre-packaged plot to give existence meaning and direction. That’s what they’re interested in, because that’s what they feel about their own lives. Certainly people have written books about such characters, so why not them? If it reads slow or aimless, then it’s literary fiction. It’s character driven. It’s intentionally mundane to reflect life. But how do you stop it being boring for the reader?