The 52-year-old actor is reportedly waiting to file his response to Angelina's divorce petition until the couple have worked out a custody deal for their six children, Maddox, 15, Pax, 12, Zahara, 11, Shiloh, 10, and twins Knox and Vivienne, eight.
A source told Us Weekly: "Lawyers are trying to work out details of the custody agreement. Brad is waiting to file a divorce response until the agreement is in place."
Angelina has requested sole physical and joint legal custody of the children but Brad reportedly wants equal access.
It was previously claimed that Angelina decided to end their two-year marriage because she was worried their constant fighting was not fair to the children.
An insider said: "[Jolie] did try to make it work, but her kids come first, and she couldn't let them see Mommy and Daddy like this. The fighting got worse, and they disagreed a lot about parenting and a lot of things."
Brad and Angelina, 41, are said to have signed a prenuptial agreement, which should make dividing up their combined $400 million fortune much easier.
Between them, the couple are said to own a total of 12 properties, all of which were bought before they married.
Seven houses are Brad's, and two are Angelina's while three others - a New York apartment, a mansion in New Orleans and a vineyard in France - were joint purchases made before they wed, and the prenup stipulates how they will be divided.
Brad and Angelina were together for 12 years and tied the knot in 2014.
It was previously claimed Brad was left "completely devastated" by the split.
An insider shared: "He is beside himself and has been crying. He was completely caught off guard and blindsided and had no idea she would do this."