When it is OK to call a blind person a jerk?

That’s the crux of the crisis facing Bill (Nick Kroll) and Rose (Jenny Slate), two single slackers with similar comedic sensibilities and a shared love for laziness and trash TV. Their late-night bar hookup should be a slam dunk, but Rose wakes in a self-loathing hangover and does an embarrassed walk of shame out of Bill’s life, refusing to even give him her phone number.

She’s got a bad track record; her last ex died when he stepped in front of a bus after an argument, and she’s got some atoning to do before she can seriously consider starting a new relationship. Bill, devastated to so quickly lose the first cute girl to show an interest in him in ages, trudges back to his day job.

He works a thankless job at a copy shop, but his real job is playing seeing-eye human to his blind brother Robbie (Adam Scott), who co-opts his brother’s body with little gratitude. Robbie’s not just blind, he’s professionally blind, a local superstar who seizes every publicity opportunity in the name of fundraising that comes his way.

Having just completed a marathon with his brother dutifully guiding the way (all 26.2 miles), he concocts a new plan to swim solo across a lake. This time he enlists some additional help, a friendly, eager new volunteer for the blind, and a pretty girl at that. Not just any pretty girl, but Bill’s pretty girl: Rose.

Neither knows. And Rose is just trying to stick to her vow to be a better person and help the less fortunate. But one pity kiss later – manipulated out of Rose with victimized showmanship – the two are officially dating.

The revelation unfolds in torturously awkward fashion, as both Rose and Bill find themselves at Robbie’s beck and call as he prepares for his swim across the lake. Also awkward is Rose’s dawning realization of something that Bill has known his whole life: that Robbie is something of a jackass.

Robbie is overbearing, conceited and unkind, and he manipulates Rose through their relationship, using her guilt and insecurities to coerce commitment out of her (he also repeatedly asks his brother if Rose is hot enough). He’s not a two-dimensional monster – obviously, his competitive streak and need for attention stem from feelings of inadequacy – but he’s obnoxiously flawed and lacks the humility to acknowledge it.

Knowing that doesn’t make it easier for either brother or girlfriend to call him on it, and they continue to attempt to assuage their feelings of guilt and duty in spite of their growing attraction to one another – one that Robbie can’t detect blossoming right under his nose.

So the question is: Just how far can decent people be pushed before they snap at a blind dude?

In “My Blind Brother,” they can be pushed pretty far, which makes for plenty of awkward chuckles and dark humor as a genuine love story between damaged souls unfolds. It’s a slight film, but one that hits all the tricky emotional and comedic notes without a hint of cruelty.

Barbara VanDenburgh, USA TODAY Network

★★★

Starz Digital presents a film written and directed by Sophie Goodhart. Running time: 85 minutes. Rated R (for language, some sexuality and drug use). Opens Friday at Facets Cinematheque and on demand.