Craig Nicholls is up early. It's three o'clock in the afternoon.

"I'm only up for this interview," he says. "I haven't been awake in the daylight for a long time. I go to sleep when the sun is coming up and wake up just after it's gone down."

He's been half-watching Ben Stiller in The Secret Life Of Walter Mitty and half-reading a Blur biography. At the age of 37, the frontman with the Vines lives in the downstairs level of his parents' home in Sydney's south, spending most of his time in the same bedroom he had as a teenager. He paints, plays guitar, writes songs, records them on his four-track, listens to his large CD collection and watches DVDs. He refuses to own a mobile phone, a computer or an iPod. Social media doesn't interest him. "I don't understand technology and I don't like it. It goes against my instinct. I have a bit of a caveman mentality."

It may surprise people to learn that Nicholls is living at home. After all, the last big news about him was in October 2012 when he physically attacked his mother. The authorities were called and in the ensuing scuffle, a policeman was injured. The family had to take out an AVO and he left home.

"It was personally the hardest time in my life and obviously a hard time for Craig," says his sister Jess Nicholls, who works with the Presets' management. "I didn't feel safe around him, which was frightening, because I love him and I've always felt closer to him than anyone else."

She will only say that Craig had "medical intervention" and the end result was that a year ago both of them returned to live in the family home.

Jess is 22, but in a strange role reversal, she has in many ways become her big brother's keeper. She says that Craig taught her to walk and talk. When her friends were watching Hi-5, she was watching late night TV talk shows with him.

"He taught me that I didn't have to conform," she says. "He taught me to have my own opinions. He gave me a totally different view of the world."

She was 10 when the Vines broke big with their 2002 debut album Highly Evolved, becoming the first Australian band since Men At Work to make the cover of U.S. Rolling Stone. She was 12 when her brother flipped out while performing at Sydney's Annandale Hotel in 2004, calling the audience sheep and destroying a photographer's camera, before it was revealed in court that he had Asperger's Syndrome. She was 15 when she took over the Vines' social media, becoming a staunch defender of her brother when criticism arose. She now acts as a "middle woman" between Craig and management and helps look after his career at times like this, with the release of the sixth Vines album, a double-disc called Wicked Nature.

"I can't remember looking forward to going to the studio so much each day as I did on this record," says Paul McKercher, who co-produced disc one and has worked with everyone from Jimmy Barnes and the Cruel Sea to You Am I and Josh Pyke. "We did a song a day and it was all done in 12 days. In the studio, Craig was a power to behold. He had the plan for each song inside his head the whole time. He's got fantastic ears and did most things on the first or second take."

The bitter break-up of the previous band line-up in 2011 means that Nicholls is the last original Vine standing – bass player Tim John and drummer Lachlan West, who are both members of the Griswolds, joined in 2012.

McKercher remembers Nicholls cracking them all up in the studio with his perfect recall of funny lines from Seinfeld, Arrested Development, Family Guy and any movie featuring Will Ferrell.

"There were points where he'd be writhing around the floor screaming into the microphone. The song would end and there'd be peals of laughter and wild applause from the band. Then Craig would stand up, peer through the glass and in this small voice he'd say, 'Oh, thanks!' He went from rock monster to this innocent kid."

Nicholls made Wicked Nature without a record deal. He doesn't have the mental fortitude or the desire to undertake a tour, although there are plans for pop-up shows.

"I have been out of my mind a couple of times in my life," he says. "To me, that's just what I'm like. When I was younger it seemed cool to be crazy. I'm not trying to be crazy now. I'm trying to be normal. What's important to me is my family and making the albums."

His day is just beginning. His media duties are done and he can return to watching a film where Ben Stiller plays a daydreamer who lives in a fantasy world. Is he happy?

"I'm like anyone. I go up and down. I'm happy and I'm mental. But I'm not completely insane."

This article features in our latest issue (#755, October 2014). Available now.