Years ago, I was heartbroken. I’d trudge through each hazy day praying for sleep, the only place where I might see the boy I missed. Shrugging off the weighted blanket of denial, I would close my eyes and meet him; sometimes in front of a church or a synagogue, sometimes in his room or mine. His smile was like a prayer answered. 

The heaviness would descend as I regained consciousness, regardless of how hard I pressed my eyelids together or how long I stayed in bed. “Hold onto that feeling,” I’d think. “It’s all you have left of him.” Without fail, I would forget, and dread would seep into its place. 

Welcome to Corsicana, Texas, or at least playwright Will Arbery’s picture of it: a hot, haunted place where the air is as thick as a dream, pregnant with the past. 

It’s here that we find Ginny, a 33-year-old woman with Down syndrome, and Christopher, her brother, unmoored in the wake of their mother’s passing. They spend their days in their mother’s stark living room, wading their way out of grief, pulled back by the tide of her constant presence. There is a lamp, a table with two chairs, and a couch made of leather like a grandfather’s bomber jacket. 

Christopher, played with piercing humility by Will Dagger, is tasked with deciphering the intricacies of Ginny’s daily care. He’s prompted by a family friend and resident guardian angel, Justice, to speak with Lot, a local artist and notorious recluse. Maybe they’ll write a song together, he hopes. Ginny loves music. That’ll help, somehow. 

Lot, whose biblical name appropriately means to conceal or cover, has no interest in notoriety, success, or connection. However, against all odds, Justice and Christopher’s arrangement coaxes all four people, each in their own distinct realities, out of solitude and into an unconventional family. 

Deirdre O’Connell, fresh off a Tony win for Best Leading Actress in “Dana H,” could choose to do anything, and understandably she chose “Corsicana.” Mr. Arbery’s rambling, masterful script is a playground for all four capable actors. 

Ms. O’Connell’s Justice is a benevolent tornado, tearing herself apart to bind others together. Lot, played by Harold Surratt, struggles admirably to accept her affection. Ginny, played by Jamie Brewer, bears her heart with brutal, refreshing honesty. 

The show is technically sparse. The set by Laura Jellinek and Cate McCrea is simple, a mirror image of a living room set on a turntable, with a retractable back wall. There is no music, save for what is played by the actors, composed by Joanna Sternberg. Each element is nearly unnoticed, perfectly serving the vision of director Sam Gold. 

Although “Corsicana” is an almost uncomfortably intimate portrait of a singular family, it’s also part of a broader theatrical trend. Pieces about disability have long existed in the canon, but pieces that include actors with disabilities have not. With Broadway’s recent revival of “Oklahoma,” and work at Theater Breaking Through Barriers and National Sawdust, that has begun to change.

“Julia often gets pigeonholed — either as angelic or pitiable, limited or blessed,” Mr. Arbery says about his older sister, who has Down syndrome and was his muse for “Corsicana.” “People tend not to consider her depression, desire, manipulation, ambivalence, sexuality.” While “Corsicana” is about disability, it’s also about humanity. 

Near the end of the play, Justice discloses that she’s writing a book. “It’s about anarchy and gifts,” she says to Chris. “It’s about small groups. It’s about community. It’s about the right to well-being. It’s about family. It’s about the dead. It’s about ghosts. It’s about gentle chaos. It’s about contracts of the heart. And the belief that when a part of the self is given away, is surrendered to the needs of a particular time, in a particular place, then community forms.” 

This play is a lot like that book — it’s the breadth that makes it so breathtaking. It’s about loving each other well. It’s about obligation and self-sufficiency, and giving ourselves away. It’s about relationships, the intricacies of which are too complicated to name. 

So, we won’t try to name them. “Corsicana is a small city in Texas,” Mr. Arbery says in his playbill note. “This play is about four people who live there. Thanks for coming.”