Ahmad Nawaz, 15, was shot in the arm during an attack at the Army Public School in Pakistan in December.
He was flown to the UK earlier this month and underwent a 14-hour procedure at the Queen Elizabeth Hospital before more surgery earlier this week.
His father, Mohammed Nawaz, said he felt "relieved" his son was "out of danger" and was sitting up and talking.
BBC Asian Network's Shabnam Mahmood said doctors had successfully treated Ahmad's gunshot wound and had inserted metal plates into his arm to mend his broken bones.
Ahmad has written an account of how he survived the Taliban attack and said he "pretended to be dead as he was already bleeding from his injuries".
He said the gunman stepped on him "with his heavy boot".
Scores of people, many of them children, were killed in the attack on the army-run school in Peshawar, in north-west Pakistan, last year.
Taliban gunmen scaled the walls of the school's compound before going on a shooting spree, killing 141 children and staff, in one of the worst assaults in the country's recent history.
The BBC's Phil Mackie said that Ahmad's parents lost one son, Haris, in the attack and feared that Ahmad would lose the use of his left arm.
The Pakistani government agreed to pay for Ahmad's medical treatment in Birmingham after a high-profile campaign in Pakistan.
The Queen Elizabeth Hospital is home to some of the world's leading experts in treating battlefield wounds.
Pakistani schoolgirl Malala Yousafzai was treated at the same hospital after being shot by the Taliban in 2012.
Malala Yousafzai wrote an anonymous diary about life under Taliban rule in north-west Pakistan, and was later shot in the head by militants.
In 2014 she became the youngest person ever to win the Nobel Peace Prize.
A Pakistani boy who was seriously wounded during a school massacre has undergone surgery in Birmingham.