"Gyllenhaal admits that he was very challenged by the script (“Brothers” is a remake of the Danish language film “Brodre,” this time directed by an Irishman).
“Just coming from Ireland it was interesting how Jim thought my character would act compared to my own American take,” Gyllenhaal says.
“There’s a moment in the film when Natalie’s character tells mine that my brother is dead, and Jim suggested I fall on the ground and make snow angels. 
I said to him very quietly I don’t know if an American would react like that.”
For Maguire, the decision to get involved in “Brothers” was down to the strength of the script and the talent involved.“I wanted to do a film that shines a light on a subject that we don’t really talk enough about,” he says.
“My character is all buttoned up and quiet about his war experiences. I think he doesn’t relate that well to his wife and children, and I think he’s living a facsimile of a life. He’s much more at home with his military family and much more comfortable at war. And it’s killing him.” Source: www.irishcentral.com
"It's there in one early scene, as the Cahill family sits down to a tense dinner. One brother — Gyllenhaal's Tommy — is just out of prison (and we don't find out for a long time why he was there). The other — Maguire's Sam, a Marine captain — is off to Afghanistan again, and eager for it. Once there, he ponders how it "almost feels like home."
Portman, as Sam's wife Grace, is the anchor who keeps the family in place: her small daughters, Isabelle (Bailee Madison) and Maggie (Taylor Geare); 
her father-in-law Hank (Sam Shepard), an ex-Marine himself; and her mother-in-law Elsie (Mare Winningham). Source: www.charlestoncitypaper.com
Stills of Jake Gyllenhaal, Tobey Maguire and Natalie Portman in "Brothers". Source: www.epixhd.comBehind the scenes of "Brothers" video