It must be the lucid moments that hurt the most, the ones that can remind those with dementia or the other madnesses of old age of just what they’ve lost and what a fog they’re trapped in the rest of the time.

That’s the big take-away from “A Kind of Madness,” a sweet, amusing, sad and just sentimental enough South African dramedy about a great love affair’s final Grand Gesture.

We meet Ellie and Daniel when they met — half a century ago — on Walker Bay. He pulled her out of the water, where flower child Ellie was “trying to remember what it was like to die.” She’d almost drowned as a little girl. When Dan figures out what she means, “morbid” or not, he’s smitten.

“Teach me how to die.”

A whirlwind romance, over the disapproval of her parents, saw them road tripping across the country in his new Ford Taunus wagon, sailing the coast on his 38 foot sloop.

But an accident is what jars Ellie awake in a hospital bed. She’s confused about where she is and why.

“You’re exactly where you’re supposed to be,” the head nurse reminds her, as she does every day. Ellie is 70ish and in Memory Care (Frail Care Unit is how they describe it in South Africa). Her panic and rages just tip us that she’s “off” her anti-psychotic meds.

Only a comforting visit from Daniel (Ian Roberts of “Tsotsi”) can calm Ellie (Sandra Prinsloo of “The Gods Must be Crazy”). But that’s no comfort. Daniel takes Ellie’s latest “I don’t BELONG here” as a call to action. They make a break for it.

Aww, he still has that same ’70s yellow Ford wagon. Isn’t that cute?

The people who don’t think any of this is adorable are their adult children. Olivia (Amy Louise Wilson) is a chef in mid-service when she gets the call. Lucy (Erica Wessels) is a psychotherapist between patients. And the youngest, Ralph (Evan Hengst) is gay and on the verge of a poolside pickup when his life is interrupted.

Lucy is the one who appreciates Mom’s illness and how scary it is for her to be off her meds. Olivia is resentful as this distraction from her life. And Ralph acts guilty as he tries to talk reason to their father when they finally get him on the phone.

No worries. Ralph turns on the tracker for Dad’s phone. Whatever merry chase Dan was going to lead them on, whatever “plan” he comes up with, the kids are right on his heels — talking a cop out of arresting Mom, chasing them across a lake or through the woods.

The flashbacks is in this Christiaan Olwagen film — he did “Poppie Nongena” and a recent South African adaptation of “The Seagull” — give it the air of “The Notebook.” But the sentimental is upended by the practical as we spend more time with the irate, panicked and bickering children. And one of her flashbacks will reveal why Ellie is haunted by visions of an opera singer dressed all in red, why that image obsesses her in her least lucid moments.

The narrative gives us plenty of reminders of how dangerous this situation is, for the demented Ellie and for anyone around her. She might get behind the wheel. She might get hold of Dan’s gun. We invest in this dubious quest, and we fear for where this is going because we all remember “Chekhov’s Gun,” and how Ellie and Dan met.

Movies tend to sentimentalize madness, but co-writers Olwagen and Wessel Pretorious jar the movie back to reality by chasing cute moments with ugly ones, and returning time and again to the children, who are reminded constantly by the expert eldest sibling how badly this could go.

Olwagen deserves a lot of credit for making this a “real world” South African story. The scenery is stunning, and there far more Black people in it than such whitewashed movies as “Semi-Soeter” would show.

Dan speaks Xhosa to his Black countrymen, and the supporting cast is as colorful as you’d expect from this milieu. Understanding, compassion and kindness rear their heads, even as Lucy is climbing onto the hood of a Black policewoman’s car in an effort to stop an arrest and “explain.” Dan doesn’t have that kind of “understanding” from a white cop.

The performances move, amuse and to a one pop — especially Wessels and Wilson as the two feuding sisters. They get the best lines.

“You’re taking this guilt trip alone!”

“What you’re resisting will persist, Liv!”

“A Kind of Madness” delivers an incredibly touching finale, and a just-mysterious-enough coda that lets us guess how this will end up. It’s wistful and sad and uplifting in unexpected ways as it underscores the prophecy of the knowing nurse (her name is omitted from any cast list I can find) who counsels the family about what’s really going on here.

“The heart always remembers even when the mind forgets.”

Rating: PG, fairly explicit sex, some profanity

Cast: Sandra Prinsloo, Ian Roberts, Erica Wessels, Amy Louise Wilson and Evan Hengst

Credits: Directed by Christiaan Olwagen, scripted by Christaan Olwagen and Wessel Pretorious. An MGM release on Amazon Prime.

Running time: 1:39