“Love After Love” is an unflinching portrait of how grief can unravel a tight-knit family in ways both banal and heart-wrenching.

In the opening moments of Russell Harbaugh’s directorial debut, Suzanne (Andie MacDowell) is seen joking with her adult son, Nicholas (Chris O’Dowd), about his father’s sexual prowess. That line comes in the middle of a deep, probing conversation about happiness.

By the next scene, Suzanne’s husband is giving an elegant toast in a strained voice (delivered with gravitas and warmth by Gareth Williams as the family’s ailing patriarch). Soon after, he is on his deathbed, and then carted out in a body bag as his family stands by, paralyzed.

Harbaugh and co-writer Eric Mendelsohn (“Judy Berlin”) convey, with startling clarity, the impermanence of life, telling their story with a messy and unpredictable pacing — echoed by freewheeling jazz flourishes in David Shire’s score — that underscores the film’s theme. “Love After Love” meanders through richly observed and sometimes startlingly funny scenes, never attempting to force the drama. The richly drawn characters stumble toward healing in ways that are refreshingly honest.

After sleeping with a work colleague, Suzanne remarks, with a mournful gaze, “I feel like I’m having an affair.” MacDowell masterfully explores the cracks that run through her character’s poised veneer, delivering her meatiest performance in 20 years.

Suzanne’s sons chart a blunter course: Nicholas self-destructively undermines a pair of relationships with infidelities, while his brother (James Adomian) cycles through fits of drunken rage, accidentally urinating in a hallway during an awkward family gathering, in a moment both hilarious and horrifying.

O’Dowd and Adomian have a volatile chemistry and enough charm to guide their characters through these unsavory choices, ultimately finding their way back to each other.

★★★1/2 (out of ★★★★)

Love After Love

When • Opens Friday, April 27.

Where • Area theaters.

Rating • Unrated. Contains coarse and sexual language, sex scenes, nudity, drugs, drunkenness and mature thematic material.

Running time • 91 minutes.