Angelina filed the court papers a minute before the courts closed on Monday night. He didn't have a lawyer or anything.
'She had threatened divorce in the past but he did not think she would file this time. He is completely devastated and beside himself. He is a shattered man.'
The source continued: 'He's extremely upset. But he is totally focused on just being helpful and making sure his kids are doing as well as possible.'
'Torn': Brad is particularly upset because he is said to not have seen his children since Angelina, who is seeking joint legal custody but sole physical custody, filed for divorce earlier in the week (pictured in 2011)
And Brad is reportedly disappointed their split had to 'play out publicly.'
'He is emotionally torn. Right now, he is devastated. He still loved Angelina and would have preferred they fight to make the marriage work,' a friend added.
'He was willing to do whatever it took to save the marriage and didn't know Angelina had already given up on it. He has wanted to protect the children. He didn't want it to play out publicly.'
Angelina filed for divorce from partner of 12 years Brad on Monday, citing 'irreconcilable differences.'
Shocking: The duo, who tied the knot in August 2014, had been together for 12 years after falling in love while working on Mr. & Mrs. Smith (pictured)
The By The Sea actress is seeking joint legal custody but sole physical custody of their six children, Maddox, 15, Pax, 12, Zahara, 11, Shiloh, 10, and eight-year-old twins Knox and Vivienne.
Meanwhile, it's been almost a week since Pitt has seen his kids. He has reportedly been apart from the children since Angelina filed for divorce on Monday, according to Us Weekly.
Brad is keen to see them as soon as possible, despite currently being under investigation by the FBI following reports of alleged child abuse.
'He knows the severity of the allegations and wants to be cleared of abuse before he sees them,' a source claimed.
Tempting fate? The two had recently starred together in 2015's By The Sea, which was directed and written by Angelia and followed a troubled married couple
'He is confident he will be cleared. The kids are asking to see Brad, so he is hoping to see them next week,' the source said.
Among the the many circulating theories about the cause of their bombshell break-up this week are reports Brad got drunk on a private jet with his family en route to LA five days earlier, and was seen fighting with his eldest son Maddox during a refueling stop in Minnesota.
And while Angelina had listed September 15 as the date she and her husband of two years separated, she had already organized a $95,000 a month home for her and her six children to live in.
Help from a friend: Angelina is said to have turned to The Tourist co-star Johnny Depp amid her split, and is also using his divorce attorney, Laura Wasser (pictured in 2010)
A source confirms to the DailyMail.com she rented the ocean front home three weeks before filing for divorce in a Los Angeles' court on September 19.
Angelina, who has hired celebrity divorce attorney Laura Wasser (who recently defended Johnny Depp through his divorce from Amber Heard), filed for divorce from Brad on Monday for 'the health of her family', two years after the couple wed at their French estate Chateau Miraval.