Pax Jolie-Pitt, the 20-year-old son of Angelina Jolie and Brad Pitt , is on the mend following a severe head injury from an electric bike accident in Los Angeles last week. "Pax has been released from the ICU," a close friend of the family tells ET. "He suffered complex trauma, and now begins the long road of recovery and physical therapy.

" ET has learned that the Maleficent star is by her son's side amid his healing journey and that his siblings have been helpful. Brad and Angelina share three biological children -- 18-year-old Shiloh and 15-year-old twins Vivienne and Knox -- as well as three adopted children, sons Maddox, 22, and Pax, 20, and daughter Zahara, 19. "Pax and Angelina are deeply grateful for the quick and life-saving action of first responders, and the outstanding medical care he received," the family friend adds.

TMZ was first to report that Pax was not wearing a helmet at the time of the accident and was rushed to a hospital for treatment after suffering a head injury and experiencing hip pain. The outlet stated on July 29, the same day of the accident, that he was stable and expected to return home quickly. According to the LAPD, paramedics were called to an accident at Hobart and Los Feliz Boulevard around 5 p.

m. after an e-bike rear ended a vehicle that was stopped at a red light. The e-bike rider was then transported to a local hospital with a severe head injury but was conscious and alert.

There is said to be no DUI or hit and run criminal element to th.