The boy, who recently graduated from St Francis Xavier's College in Newcastle, followed the thieves when tragedy struck.
According to his cousin Taren Brown, when Lawson's friend's caught up to him, they were met with the horrifying sight of his scooter lodged in a concrete drain filled with water.
Using their lights from their phones, they discovered Lawson's unconscious body face down in the sewer. The helmet he had been wearing was completely destroyed by the impact.
The boys managed to retrieve their friends body before performing CPR as locals phoned an ambulance.
He was then rushed to Bali International Medical Centre but has remained unconscious since the incident.
Lawson has undergone surgery for a head wound and has been left with around 20 stitches caused by his crushed helmet.
However, the biggest concern for his family is the brain haemorrhage he suffered and infection from the water in his lungs.
A GoFundMe has been established to help raise funds for the teen and his family who have been burdened with huge medical bills.
While Lawson did take out travel insurance prior to his dream holiday, he was not licensed to ride a motorcycle and therefore, his medical bills are not covered.
It's understood that once Lawson is able to be flown home for further medical treatment he faces a long road of rehabilitation.
'It will be one step at a time, but an expensive journey, if we all pull together we can make a big difference,' his cousin wrote on the fundraising page.