You cannot travel by boat from Afghanistan to Australia.
Reason: Afghanistan is a landlocked country in Central Asia. It has no coastline, no seaports, and no navigable rivers connecting to the ocean. The nearest sea—the Arabian Sea—is ~500 km (300 mi) south across Pakistan or Iran.
Actual Routes from Afghanistan to Australia:
Any "boat" claim is a misunderstanding. Afghanistan's geography makes maritime travel impossible without first crossing at least one international land border.