Both men are self-styled scribes (Jonathan has been composing an epic novel in his head for decades; Nick scrawls navel-gazing poetry), and drunks with delusions of grandeur. Weitz lets each take turns as patently unreliable narrator. Their internal monologues seem to know they're on a split schedule. "Don't worry, you're back in the hands of a master storyteller," Jonathan says when we cut back to his perspective after a stint with Nick, but Weitz isn't interested in exploring the meta possibilities of this approach.
DeNiro might as well be wearing a mirrored sandwich board in his every scene opposite Dano, as the theatrics of his dissolving mental state are so blatantly a device to force Nick to confront a reflection of his own demons and fears (his mom's suicide, his escalating addictions, his ability to commit to neither women nor career). This subtext is turned into text in a climactic confrontation scene. "You are me! I made you!" Jonathan yells at Nick. The son's response? No, I'm not!
Being Flynn is as over-edited as your standard contemporary shoot-em-up. What the actors are unable to get across emotionally (which is a lot — Dano and DeNiro, both of them all big, actorly tics, often seem like they were filmed in different rooms), Weitz hammers home via near-constant music. A welcome-to-the-shelter montage riding along on a breezy source cue? Uh, sure, okay. A major character's suicide dramatized via what amounts to a Badly Drawn Boy music video? Yikes.
Nick Flynn's second memoir, The Ticking Is the Bomb, partially chronicled his relationship with a woman he called Inez,a stand-in for his now-wife, actress Lili Taylor. Bomb is implicitly referenced in Being Flynn through the casting of Taylor in a small role and the casting of black actress Kelly McCreary in a single scene as Nick's new wife Inez. The racial makeover of the Inez character seems intended to force the point that the son has taken a different path than his casually racist dad. It's the ultimate example of the way Weitz insists on reducing human complexities to black and white.