The mother of 14-year-old William Callaghan has thanked his rescuers, after he was found alive and well after two nights lost in freezing temperatures at Mount Disappointment, north of Melbourne.

The teenager, who is autistic and non-verbal, was found in bushland by volunteer Ben Gibbs about lunchtime on Wednesday.

“More than anything thank you, everyone. I’m so grateful, you’re all amazing. What an amazing community,” Will’s mother, Penny Callaghan, said.

“I want to be with my boy. I couldn’t believe it [when he was found], I can’t imagine what he’s been feeling and going through.”

Ms Callaghan said she was overwhelmed by Wednesday’s events, but her son was “quite calm, considering”.

“He has used (a program)… to tell us that he is confused and is scared. He keeps pressing the body, saying his body feels weird,” she said.

“His first request was McDonald’s. I think he wanted hot, salty food.”

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Mr Gibbs, who grew up in the area, found Will about 20 minutes off the track, deeper in the bush than previous searches had covered.

“He was just about 15 metres from me, just standing there, he was really angelic, just standing,” he said.

“He looked in reasonable health, he wasn’t shivering too bad. He didn’t have socks on so I put some socks on him and a jacket. I gave him some chocolate.”

Mr Gibbs said felt like he was on track to finding William before discovering the teenager.

“This is kind of our family mountain. I’ve been going here since I was a boy, so I know it well,” he said.

Will Callaghan is reunited with his mother, Penny. Photo: AAP

Will, who was wearing only a blue hoodie and track pants when he vanished on Monday afternoon, got lost after becoming separated from his family on the Mount Disappointment summit on Monday afternoon.

An air and ground search was launched for him later on Monday but there had been no sightings of him before Mr Gibbs’ discovery on Wednesday.

Victoria Police thanked the community for its outpouring of support during the three-day search through difficult terrain.

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Acting Inspector Christine Lalor said the teenager was found about 1.5 kilometres from the command post and about 10 minutes off the track in bushland.

“What an amazing result, I have so many people to thank,” she said.

She said Will had taken off his shoes, and was wearing only his socks.

After being found, Will was taken to the search staging area, where blue tarps were erected to shield his reunion with his family, during which he gave Ms Callaghan a hug. The surrounding crowds of jubilant rescuers were told “no clapping, no whistling, no cheering” as he emerged, because that might frighten him.

By 2pm, he had left in an ambulance – with his mother and stepfather Nathan Ezard – for a check-up in hospital.

Overnight, searchers used thermal-imaging equipment and blasted music, including William’s favourite tune, Thomas the Tank Engine, in the hope of drawing him out of the bush.

Hundreds of people had combed the area, as food was left out for him to find while temperatures plummeted.

A wave of relief went through the camp when news broke of the boy’s discovery.

The breakthrough came just hours after Ms Callaghan fronted the media with a heartfelt plea for her “beautiful, beautiful” son to be found.

“If he has reached the urban environment at this point, he will look out of place,” she said.

“He will be quite scared of loud noises and he’s wearing navy blue. I’m hoping he still has his clothes on. He may be barefoot, though. He doesn’t like shoes.”

“Any parent, I’m sure would be thinking the worst-case scenario. I can’t do that at the moment. I’m really hoping that we find him today. I don’t want him out another night.

“I am not the praying type, but I’m praying now, because I want him home”.

-with AAP