Everyone is juggling a multitude of problems in “Goodbye June” — some bigger than others, though they combine to give this holiday-season drama a greater-than-usual air of December frazzlement. “All I want is a cancer-free mother and some fucking sheep’s yogurt,” moans Andrea Riseborough’s short-fused homemaker Molly: issues presumably listed in descending order of importance, as the script lands one of several jabs at bourgeois middle-class priorities. It’s a slightly odd satirical note to repeatedly strike in a film with wholly A-list pedigree. Written by 21-year-old Joe Anders and directed by his mother Kate Winslet, this simple, sentimental family portrait lacks the ring of lived experience at more than one level.

The not-cancer-free mother in this case is (you guessed it) June, played with stoically good-humored poise by a bedridden Helen Mirren, persistently smiling against the dying of the light. Given less than a month to live by doctors after a series of failed chemotherapy treatments, and choosing to see out her time on Earth in a private hospital room in the English town of Cheltenham, she’s the calm locus around which the rest of the film’s characters flap, flutter and squabble. Her impending demise, racing for second place against the imperilled family Christmas, provides a tight deadline for the resolution of various lingering feuds and hidden truths.

Thus is the stage set for a familiar but potentially affecting tale of nearest-and-dearest bickering and bonding, designed to have viewers weeping into their eggnog during a tonal break from Netflix’s frothier seasonal fare. (After a brief theatrical run, “Goodbye June” hits the streaming platform on Christmas Eve.) But the film never quite locates the heart, in large part because it never cracks its collective of variously dissatisfied characters — all of whom want for interior life and detail beyond their present unhappy circumstances. For her first venture behind the camera, Winslet has unsurprisingly assembled a murderers’ row of co-stars, so it follows that her largely prosaic direction is preoccupied with performance above all else. There’s a lot of acting here, little of it peak-form for the talent involved, though the ensemble lifts and colors Anders’ sometimes heavy-handed dialogue.

If Winslet herself gives the film’s best and most carefully modulated turn, it’s not because she’s given herself the prize role. As Julia, the eldest and most responsibility-burdened daughter of June and her checked-out husband Bernie (Timothy Spall), she carries herself with the brisk but unassuming posture of one accustomed to thankless tasks. A career woman with an absent husband and a gaggle of kids who bound boisterously through proceedings without asserting individual personalities, she’s a more stable presence than her sisters: the aforementioned, highly-strung Molly, also bringing several children to the party, and single, new-agey free spirit Helen (Toni Collette), who has been living abroad.

A fourth sibling, withdrawn younger brother Connor (Johnny Flynn), has never flown the coop, dedicating his life to looking after his increasingly incapable parents. Another reason for his generally repressed state soon becomes obvious — “Just live your life, just be exactly who you are,” his mother implores him from her deathbed, lest viewers not get the idea — though it’s one subplot left mostly to subtext in a script that otherwise tends toward talky overstatement.

Either way, there’s little time for his baggage between the more pronounced dramas of his sisters: Julia and Molly have been on barely-speaking terms for years, although, as is so often the logic in such films, they’re just one heart-to-heart away from hugging it all out. From the sidelines, an indefatigably kind and patient nurse (Fisayo Akinade) observes these fractious family dynamics with a rueful twinkle, gently counseling the dying matriarch as to how to bring her brood back together. His name is Angel, and such is the level of subtlety the film settles for.

Give or take a few characters in this heavily populated affair — the audience may share in June’s palpable relief when she’s finally left alone to watch “The Great British Baking Show” with the reliably soft-spoken Angel — the premise of “Goodbye June” can’t help but recall a superior Netflix release from last year: Azazel Jacobs’ “His Three Daughters,” which likewise probed and tentatively mended rivalries between siblings converged for a parent’s last days. But where Jacobs’ script was rich in novelistic specifics and nuances of personality, Anders’ abounds in blind spots that leave everyone on screen more a concept than a character. We’re repeatedly told that Julia’s job has challenged her commitment to her family, though we never learn what she does. Ditto where Helen has been living, and why, or the particulars of June and Bernie’s long but seemingly passionless marriage — though Spall does get to sob through a lengthy karaoke number in his wife’s honor.

Lest things get too glum, “Goodbye June” rallies at the eleventh hour with an elaborately cutesy let’s-put-on-a-Nativity-show sequence that, if nothing else, shores up its holiday-movie credentials beyond the tinsel-draped set-dressing and assorted carols embellishing Ben Harlan’s plaintive, piano-heavy score. (Even the lensing, by the accomplished Alwin H. Küchler, is relentlessly warm and gold-flecked: No NHS hospital ward has ever looked so homey.) The family that plays together, it turns out, stays together. Like much else here, the scene is a deflection from harsher mortal realities: Angel declares that his professional mission is to give all his patients “a good goodbye.” Putting to one side any uglier consequences of illness or less fixable emotional wounds, the film follows suit — though there’s only a glancing sense here that death is for life, not just for Christmas.