An airman who vanished following a night out developed a “significant binge-drinking problem” after a friend died on a railway line when he was a teenager, an inquest heard.
Corrie Mckeague, from Dunfermline, was 23 when he vanished in Bury St Edmunds, Suffolk, on 24 September 2016.
Police believe he died after climbing into a waste bin after a night out.
The inquest, due to last four weeks, is being held at Suffolk Coroner’s Court in Ipswich.
The last confirmed sighting of Mr Mckeague was at 03:25 BST, when CCTV cameras recorded him walking into an area in central Bury St Edmunds known as the “horseshoe”, behind Greggs and Superdrug, where industrial waste bins were stored.
A £2m police investigation was carried out into his disappearance, including a trawl of a landfill site at Milton, near Cambridge. His body has never been found.
In a statement read out at the inquest, Martin Mckeague described his son as a “happy child”.
However, Mr Mckeague said there were “major events” that shaped his life including the separation of his parents when he was 10 years old and the discovery of his friend’s body on a railway line when he was 15.
“I believe Corrie developed a significant binge-drinking problem,” Mr Mckeague said.
He said the death of his son’s friend “was a terrible shock for a 15-year-old boy to suffer, and one I don’t think he ever truly got over”.
Martin Mckeague continued: “I don’t believe Corrie was ever suicidal.
“This has been a heart-breaking tragedy.”
Mr Mckeague’s mother Nicola Urquhart agreed the friend’s death had a “huge impact” on her son.
In a statement read to the inquest, she said Corrie, who had started to train as a hairdresser and then as a PE teacher before joining the RAF, had been prescribed antidepressants in the past.
But, she said, he was “back to his usual happy self” by 2015.
Ms Urquhart said her son “regularly lost his phone or wallet on nights out” but “was never aggressive with or without alcohol”.
“There was nothing to suggest Corrie had any problems or concerns around the time of his disappearance,” she said.
Ms Urquhart said added: “Despite what’s in the press, as far as I’m aware Corrie had never slept in a bin nor had he ever climbed into a bin to sleep.”
Suffolk’s senior coroner Nigel Parsley said Mr Mckeague, who had served in the RAF for three years, drank a “significant amount of alcohol during the evening” of 23 September.
He said Mr Mckeague was asked to leave Flex nightclub and “was seen on a number of occasions on CCTV”.
Mr Parsley said police investigations and searches failed to locate him and there had been no contact with family and no financial transactions that could be linked to him.
He said over the coming weeks, jurors would hear evidence about Mr Mckeague’s movements, his contact with any witnesses and “hypotheses and possible scenarios relating to Corrie’s disappearance”.