Heroes of the Zeroes is Nick Rogers’ daily, alphabetical look back at the 365 best films of 2000 to 2009.

Like Billy Wilder with a British bent, 2002’s About a Boy lithely danced on the wire of uneasy scenarios for comedy — attempted suicide, fragile kids of divorce, childhood bereft of memorable experiences. But it never trivialized them, humanly emphasizing life’s quality over its quantity.

Boy represented the apex before a befuddling downward career trajectory for brotherly filmmakers Chris and Paul Weitz — who afterward slid into a mire of lame fantasy-literature adaptations (Chris’s The Twilight Saga: New Moon and The Golden Compass) and limp satire (Paul’s American Dreamz).

Here, Hugh Grant turns his popular persona of charming cad on its dramatic ear as Will, a shiftless, aging layabout living off royalties from his father’s Christmas song. While scheming to date single moms, Will inadvertently mentors Marcus (Nicholas Hoult), a 12-year-old whose suicidal mother (Toni Collette) isn’t necessarily the role model he needs.

The Weitzes tenderly examine the difference between parenting and projecting onto your child in scenes when Collette faces her actions’ consequences and when Hoult measures how to prevent her self-destructive cycle from starting over again.

Boy sounds like a downer, but it’s got joie de vivre even in its most morbid moments. Grant gets one of his greatest one-liners — “I’d never watched a woman cry without feeling responsible before” — but his life is itself a one-hit wonder which, like many novelties, fades into background noise.

When Will uttered “I loved him. I really loved him” about Marcus, it turned a winning comedy into rumination on the unfettered selflessness of true friendship.