The 24-year-old's shocked family and friends are rallying to raise money to help pay mounting hospital bills of at least $20,000 after the crash last Sunday, with fears he will be stuck in Bali until the medical expenses are paid.

Initially the hospital demanded $7000 upfront for Mr Rudd's surgery from his twin sister Tanika Rudd, but due to the seriousness of his injuries they went ahead with the operation to insert a plate in his skull and stop internal bleeding after he crashed his bike into a tree.

Mr Rudd's friend and Common Grounds Gowrie cafe workmate Corey Garcia is helping to raise funds to cover the medical costs through an online page set up with help from workmate Nathan Reynolds.

"We've tried everything we can do, we don't know what else to do," Mr Garcia said.

"At first it felt a bit distant, but once I saw photos and spoke to him over the phone it was pretty upsetting.

"He doesn't sound like himself at all, he repeated himself a few times and he couldn't build conversation."

Mr Rudd started working as a cook at the cafe after moving to Canberra last August.

He recently left his job to go travelling, but Mr Garcia said the cafe staff had been looking forward to his return.

Mr Rudd's aunt, Virginia Wood, from Kambah, said it took a while for the reality of Mr Rudd's "horrific" accident to sink in when she was contacted by his Sydney-based twin.

"It sort of spun me because they wanted $3500 before they operated and then [another] $3500 before they let him out of hospital and that's got to be paid," Ms Wood said.

"Because his injuries were so bad they had to operate or otherwise he would have died."

Ms Wood said she couldn't bear to look at the graphic photos of her nephew lying in a hospital bed.

"As soon as I saw it I cried, I can't look at those photos," she said.

"They [the twins] lost their mum 12 years ago and she [Miss Rudd] just can't lose Liam."

Until she arrives in Bali, Miss Rudd won't know the full extent of her brother's injuries or if he has insurance to offset his medical bills, which currently sit at about $20,000, including a $7000 surgery bill and $1000 for each day of his stay in intensive care.

She has learned his teeth and eyes were unharmed in the crash, but he still has swelling on the brain and short-term memory loss.

Ms Wood covered the cost of a fast-tracked passport for Miss Rudd to fly to Bali on Saturday to be by her brother's side.

"He just kept on asking for her and wondering why she wasn't there," Ms Wood said.

"He had a bit of short-term memory loss so he was getting really agitated.

"As soon as she's over there he will calm down instantly - as soon as he sees her."

Mr Rudd lived with Ms Wood and her family in Kambah when he first moved to Canberra, before he found a share house at Richardson.

The family are relieved Mr Rudd's memory appears to be improving and Ms Wood said he had even began asking after his beloved cat Gizmo, who was being taken care of by his housemates at Richardson.

Donations towards Liam Rudd's treatment can be made online: www.giveforward.com/fundraiser/qck7/liam-rudd-s-motorcycle-accident-treatment-fund.

- With Tracey Prisk