Philip Seymour Hoffman and Laura Linney portray estranged siblings in The

Estranged brother and sister Jon and Wendy Savage (Philip Seymour Hoffman and Laura Linney) are screwed-up and self-absorbed, but they certainly seem realistic. Sometimes they’re shrill, sometimes they’re scared, often they’re incredibly thoughtless and have no qualms about lying to each other.

But as they come together to deal with one of the trickier aspects of growing into middle age – caring for an elderly parent – they make plenty of mistakes. And that’s realistic, too.

Writer-director Tamara Jenkins, in her first film since the 1998 comedy “Slums of Beverly Hills,” recognizes the difficulty of having to function as a mother or father to the person who raised you, and she depicts it with brutal honesty and absurd humor in “The Savages.” (Her script was inspired partially by her own father’s dementia, and it features one of the loveliest, most perfect endings you’ll ever see.)

It certainly helps a great deal that Jenkins has consistently nuanced performers in Hoffman and Linney. And Tony Award winner Philip Bosco is unpredictable and frequently heartbreaking as their irascible father.

Jenkins begins by presenting patriarch Lenny Savage’s existence in Sun City, Ariz., as a surreal, candy-coated wonderland of golf carts and aqua aerobics. Then one day he reaches into the toilet and calmly writes on the wall with his own feces – an early warning of where Jenkins plans on going in terms of tone.

Jon and Wendy reluctantly arrive to handle the problem of their aging father’s worsening state just as Dad’s longtime lady friend dies. Now they have to figure out what to do with him – or, more pertinently, where to put him.

Wendy, a high-strung, would-be playwright who barely earns a living as a temp, lives with her cat in a cramped Manhattan apartment, desperately applies for grants she never receives and is having an unhappy affair with her married, balding neighbor, Larry (Peter Friedman). She can barely manage her own life, much less someone else’s; nevertheless, she approaches the prospect of finding her father a home with thorough Type-A vigor.

Jon is doing only slightly better. Rumpled and blase, he’s a college professor who lives in a rambling home in Buffalo, where he’s forged a career writing books about subjects few people care about. He’s on deadline, he’s in denial that his Polish girlfriend (Cara Seymour) is leaving because her visa has run out, and he’d rather deal with his dad as quickly and painlessly as possible.

So maybe it’s a bit obvious that the Savage siblings are opposites in temperament, unwilling to acknowledge that they need each other. Although they rarely talk, they’re still competitive, albeit in a passive-aggressive way.

One thing they can agree on, though, is that whatever sort of housing they find for their father, they’ll be taking better care of him than he ever did of them, and that knowledge fortifies them.

Despite its dark humor, “The Savages” tackles the tough topics of aging, frailty, humiliation and death. All depressing stuff, to be sure, but Jenkins handles it with a delicate, relatable touch, and without being maudlin.

“You don’t think it’s self-important and bourgeois?” Wendy asks of Jon when she finally gets her semi-autobiographical play produced. Maybe just a little – but that doesn’t mean it can’t be moving, too.