Was the "dangerous drug" a Schedule 1 "hard drug" or a Schedule 2 drug?
I assume that your nephew was charged with trafficking under section 5 of the Drugs Misuse Act 1986 (Qld).
If your nephew was charged under the Drugs Misuse Act 1986 (Qld), there is no minimum penalty - only a maximum penalty:
Trafficking of a Schedule 1 drug - up to 25 years imprisonment; and
Trafficking of a Schedule 2 drug - up to 20 years imprisonment.