As an attempt to address the realities of post-9/11 trauma, Reign Over Me is so misbegotten that it trivializes the subject. Adam Sandler plays Charlie Fineman, who has retreated from his life after losing his wife and daughters in the attacks. He resides alone in the Manhattan apartment he once shared with his family, renovating it compulsively, listening to rock and roll, tooling around the city on his motorized scooter and attending revivals of classic comedies. He’s given up his dental practice and he won’t see his in-laws (Robert Klein and Melinda Dillon) or anyone who might remind him of the familial paradise he once enjoyed.

The movie is told from the point of view of Charlie’s college roommate and dental-school pal Alan Johnson (Don Cheadle), who comes across him one day in the street and renews their friendship. For Charlie, Alan represents a happy time in life when he was as footloose as he acts now. The recaptured camaraderie of youth also appeals to Alan, who is struggling with the demands of marriage and fatherhood.

The idea that a man who has seen his whole life go up in smoke might want to return to his adolescence is psychologically convincing and dramatically powerful. It even has the potential for a Pirandellian examination of how a reality we can’t face might alter our perceptions of who we are. Though Sandler isn’t much of an actor, his childlike qualities—for example, his ability to access the intense anger of a thwarted teenager—work well in the role. (Alan discovers that any attempt to confront his old roommate with his loss rattles him so badly that he becomes paranoid and destructive.)

But there’s something queasy-making about the way writer-director Mike Binder uses Charlie’s personal tragedy to fix Alan’s marriage—he becomes more communicative with his wife (Jada Pinkett Smith) and more emotionally available. Alan also becomes more assertive with the partners in his dental practice. (Their high-handed treatment of Alan, who started the practice, doesn’t make much sense; the story is rigged so that Alan will have some outrage at work to stand up against.)

Cheadle has done brilliant work in an extraordinarily varied series of roles; his specialties, whether he’s playing dangerous characters like Denzel Washington’s violent pal in Devil in a Blue Dress and the prison bully in Out of Sight, or heroic ones like the real-life hotelier Paul Rusesabagina in Hotel Rwanda, are his ability to shift tones on a dime and his gift for conveying unusual, complex emotional states casually, without revving up. But his role in Reign Over Me is so badly written that he sinks under it.

In order to set up the notion that Charlie’s freewheeling lifestyle elicits Alan’s envy and then his vicarious participation, Binder makes Alan bizarrely insensitive, and in ways the movie doesn’t always acknowledge. Alan first broaches the subject of Charlie’s family in the context of pointing out that now Charlie is free to sleep with any woman he desires. It doesn’t appear to have occurred to Binder that the remark makes Alan look not like a man who longs for unfettered youth but like a callous boor. We’re supposed to believe that Alan is reasonably intelligent, yet it takes him ages even to figure out that Charlie’s affect is weird and that he’s operating with some kind of psychic deficiency.

Binder’s previous movie, The Upside of Anger, dealt with another sort of loss—the departure of the protagonist’s husband—in a way that was simultaneously comic and emotionally plausible. But with the significant exception of Charlie, the characters in Reign Over Me mostly conduct themselves in such baffling ways that you sometimes feel you’re watching Martians. Charlie’s in-laws, for instance, who are trying to get him committed to a psychiatric hospital, think he’s crazy because he doesn’t mourn as they do, poring over old photographs and bonding with them over their common grief.

Then there’s Alan’s patient Donna Remar (Saffron Burrows), a young woman whose response to being abandoned by her lover is to throw herself, repeatedly and embarrassingly, at Alan and then threaten to sue him when he sends her home. Somehow Binder imagines that Donna’s condition (which is played entirely for laughs) can be healed by her dating Charlie.

The movie is full of sympathy for people like Charlie, who live in bunkers devised by their own shattered psyches. Yet everything it constructs around his story is so preposterous that our sympathy is cheapened.