Here you've got to look at the Drugs Misuse Act and Drugs Misuse Regulation. The potential penalties depend on what he is charged with: usually either 'possession', 'supply', or 'trafficking'.
If it's possession: Between 2.0g and 200.0g of methylamphetamine - maximum penalty of 25 years (20 years if it is established they are a 'drug dependent person').
If it's supply: depends on the circumstances (maximum penalties range from 15 years to life).
If it's trafficking: maximum penalty is 25 years.
You can get some general information here:
Drug Offences and Penalties in Queensland
There may be other charges involved as well.