Billy was enjoying his two-month-long holiday when the accident happened.
The 29-year-old suffered multiple fractures to his skull and traumatic brain damage.
A landslide triggered by the quake killed two of the victims.
The suspected mastermind Abu Bakar Bashir walked free from prison after serving 10 years of a 15-year sentence.
Officer Wayan Sudarsa was found dead with 42 wounds in August 2016.
