The Lyons, the toxic clan who give their name to Nicky Silver’s play, are the kind of dysfunctional family that make other dysfunctional families look not just good, but positively wholesome.

The Lomans, the Wingfields, the Macbeths and the Tyrones in O’Neill’s Long Days Journey into Night? They’ve got almost nothin’ on the Lyons, mother and father, daughter and son, who, in a lacerating two hours at Shaker Bridge, set up a circular firing squad.

The set-up is similar to other sitcoms or plays featuring an urban Jewish American family: Ben Lyons, played by Shaker Bridge founder Bill Coons, who also directs the play, is in a Manhattan hospital room dying from cancer. His wife, Rita, is with him when Lisa, their daughter, and Curtis, their son, visit him.

Here you might expect a conventional TV scenario to play out: a family that’s had its differences over the years reunite and find common ground over the patriarch’s death bed. Jokes at each other’s expense are made, tears are shed and the familial rift is healed.

Emphatically: No.

Ben and Rita are the kind of parents who eat their young, and their bitter children, who have never enjoyed their parents’ whole-hearted love and support, are all too happy to throw their parents’ neglect and cruelty right back at them. Here, the prospect of their father’s death is an acid punch line.

It turns out that Ben has made his virulent dislike of his gay son all too clear, while daughter Lisa is an alcoholic who has made the wrong choices in men. Ben spares no sentiment for his family. The only person he mourns is his late father, who was, in Ben’s view, a man among men.

Then there’s Rita, who is really the heart and soul of the play. At first glance, she seems the type of garden-variety suburban New Jersey housewife beloved of a hundred sit-coms, nattering on about interior decoration while her husband withers away in a hospital bed.

Beneath the conventional you-don’t-write, you-don’t-call facade, though, there’s a woman who has had to suppress her desire for a very different life, a very different husband. And when she liberates herself from her family in the second act, it feels right, as if she managed to fling herself into a lifeboat and row madly away.

Silver has made a 20-plus year career out of writing comedies, or dramedies, that push at the constraints of realism, and taste. The Lyons family is more surreal, than real. And there are no filters. The family members say exactly what’s on their minds, no matter how bilious, petty or mean-spirited.

At the same time they’re fabulists, the lying Lyons. When reality is too much to bear, they invent their own. Curtis, a short story writer, has made himself the subject of his own story: he dissembles as if it’s second nature. When, in Act II, Curtis goes to look at a new apartment with a realtor, his gift for invention redounds on him in a singularly unpleasant way. Lisa doesn’t so much lie, as omit. And what she omits is crucial.

The Lyons is an exhausting play to watch in some ways, and although there are plenty of laughs, they teeter between uneasy and shocking. There are precious moments when real human emotion breaks through, but they’re sporadic.

The standout in the cast is Dorothy Stanley, who plays Rita. She has been a regular in Northern Stage and Weston Playhouse productions and has previously acted with Shaker Bridge in Don’t Talk to the Actors.

As Rita, Stanley punctures everyone’s deceit. She sees through the ways her children and husband console themselves with their versions of their lives. She slips in the stiletto so expertly you don’t feel the edge of the blade until it’s on its way back out.

Stanley deftly conveys Rita’s aplomb, and her sense of self-preservation. She puts across the way mothers can feel disappointed and betrayed by their children and yet love them and want the best for them. Having not achieved what she wanted in her own life, she just can’t help but pick at her children, prodding them toward the kinds of lives she thinks they ought to have. Stanley also astutely expresses the inconvenient truth that if Rita’s children aren’t the paragons she imagined, much of the blame lies with herself, and her husband.

Bill Coons plays Ben with a surly disgust. What a tragedy to have reached the end of his life and feel such a grating dissatisfaction at how it’s all turned out. Coons is one of the smartest directors around, and I don’t know the circumstances behind the decision to cast himself, but it was not perhaps the ideal choice.

Coons gets a lot of laughs from the alacrity with which he deploys the f-word, and he has one moment in which he describes meeting his late father in the afterlife that brought me to tears, but on the whole his vocal inflections stay more-or-less at one level, when you might expect them to rise, fall or show variations in tone and pitch that humans use under stress.

Taylor Wright hits the right notes as Curtis, whiny one minute and apparently the only mature one in the family the next. Sarah Hartman plays Lisa as a petulant child, and that wears thin, although the flaw lies in Silver’s writing for the character. He’s on stronger ground with Curtis and Rita.

Paul West, who plays the realtor Brian Hutchins, shows a natural ambivalence and wariness in the part of a man confused by Curtis’s mercurial behavior when Hutchins shows him the apartment. Curtis knows more about Hutchins than he initially lets on, which abruptly turns into an unexpected stand-off. Again stubborn reality breaks through the fictions that Curtis has written for himself.

The one sane person in the play is the nurse, who doesn’t have much patience for all the theatrics. Lanni West, Paul West’s wife, exudes practicality, warmth and grit in the role.

Silver holds out a little beacon of hope at the end of the play for Curtis when he and the nurse settle down for a real conversation. That doesn’t quite ring true, given the snarling that’s gone before, but it’s understandable that Silver didn’t want to end on a wholly bleak note.

The Lyons runs through May 22 at Shaker Bridge Theatre in Enfield. For tickets and information call the theater at 603-448-3750 or go to shakerbridgetheatre.org.