His older sister Natalie Commins said the Australian High Commission notified the family early this morning that her brother had been found in hospital near London.
“We don’t have much information about his hospitalisation and had an extremely short call with dad who is now in London asleep,” Miss Commins said.
“We know that he is medically stable and not in imminent danger for his life,” she said.
Mr Commins had been in the UK for a five-week European Contiki tour, followed by a week in Iceland with family friends.
He returned to London and was expected to spend two nights in the city before flying back to Australia, but he never boarded the flight.
Miss Commins said the family had since learned that there was a problem with the second night’s accommodation in London.
“We don’t know if he ended up anywhere,” she said.
“We know he was hospitalised on June 1, but he was unable to contact his family.”
Miss Commins said it was “strange” that more than a week had lapsed between her brother being admitted to hospital and the family being notified in Australia.
She said they would seek more answers from authorities in coming days.
Mr Commins’s bank account was last accessed via ATM on May 30 at Yotel Heathrow Airport and his sister said authorities had not confirmed who used the card.
“We think it was Riley who withdraw 65 pounds, which was declined due to insufficient funds at Heathrow Yotel ATM, but we have not had this confirmed by any footage.”
She said her mother and Mr Commins’s girlfriend realised he was missing after they waited at the Brisbane Airport for two hours when he was due to arrive, only to learn that he never boarded the flight.
“He was not heard of at least a day before this, but we assumed he was catching up on sleep, although mum was starting to worry,” Miss Commins said. “It is not in Riley’s character to disappear.
“He was really looking forward to coming home and was in good spirits throughout his trip.”
The family notified authorities including the Department of Foreign Affairs and Trade, Interpol, UK police and Australian Federal Police and launched the Facebook page “Help Find Riley Commins”.
Thousands of people shared the page’s posts on social media and Miss Commins said that may well have contributed to her brother being found.
“Please thank the community once again for us,” she told the ABC.
“They very well could have produced a lead that led us to Riley.”
Miss Commins said her “street savvy, independent, sociable” brother was oblivious to the international attention, but in a Facebook post on his page this morning, he extended his own thank-you.
“I appreciate everyone concern am all well and good! I had no access to my phone or any devices to reach people sorry!” he wrote in a post.
Mr Commins’ father is expected to remain with his son until he is well enough to return to Australia.