A military doctor -- who went to Turkey to retrieve his son from the Islamic State group, but was killed in the Istanbul airport attack -- has been buried in his home town in Tunisia.

Family, friends and uniformed officers attended the ceremony for Colonel Fathi Bayoudh, head of the pediatric service at the Tunis military hospital. The Tunisian government said he was among the dozens killed in Tuesday's suicide bombing. Bayoudh's twenty-five-year-old son, Anouar, is among thousands of young Tunisians who joined the Islamic State amid the country's post-revolution economic turmoil. He is now in Turkish custody awaiting extradition.

The funeral of Colonel Major Fathi Beyoudh [Fah-tea Bay-ude] was attended by many of his friends and family. He had spent his life caring for others. His career saw him work as a paediatric doctor at the military hospital in Tunis. And as a humanitarian in refugee camps.

 "He is a man who devoted himself to medicine and volunteering. He went to wherever there is an earthquake or a war or civil war to help people，" said Dr Mohamed Hedi Gueddich, colleague of Dr Bayoudh.

Dr Bayoudh was killed in Tuesday's attack on Istanbul's Ataturk airport as he waited for his wife to arrive on a flight from Tunis.

They had been trying for months to get their only son out of Syria.

Anouar left his family last year. Like many ISIL recruits he went to Turkey. From there he found a route via Iraq into the ISIL stronghold of Rawya, where he became a medic for the group.

But by April this year he had changed his mind. He messaged his father asking him to help him get out.

Dr Beyoudh traveled to the south of Turkey. He was trying to establish contacts and smuggle his son out of Syria. His wife says he never gave up hope...

"He was introduced to Syrians from the Free Syrian Army by phone and they sent a smuggler to get him out. This happened in secrecy using either whatsapp or viber," said Saida Beyoudh, wife of Dr  Bayoudh.

Once out of Raqqa, Anouar was held by the Free Syrian Army for weeks. He said he thought he was going to be killed. In the meantime, Dr. Beyoudh was trying to get him to the Turkish Army.

This was his last conversation with his son ...

 "He said he wanted to know the truth, and he thought he could find it in Daesh, but it is a scam. He wrote this on Sunday because he was hopeless, so he told him "my son I will sacrifice my soul for you"," Saida said.

His father was killed that same day trying to save him. His son Anouar was moved to the custody of the Turkish Army. He is now being repatriated to Tunisia.

"His goal was to bring back his son from Syria, and he went there and saved his son from Daesh," said Abdallah Toumi, cousin of Dr Bayoudh.

"Dr Beyoudh's last mission was probably the one that mattered the most in his life. Today his success in bringing back his son leaves a memory of an exceptional hero and father, and inspires thousands of other parents who lost their kids to ISIL.