Bringing Prescription Drugs in to Australia

My family is visiting Australia in mid-May (US Citizens). My research says that we need to have Drs letters for our prescription medication. My son takes ADHD medication and sleep medication that are prescribed by a Psychiatrist. We are trying to get a letter from her, but they are not being responsive and told him he needs to get one from his family Dr., except the doesn't have one. What other options do we have? If we bring the medicine in the original bottle, will that work? Or do we just keep begging them?

Any help would be appreciated. He would have a very bad trip if he doesn't have his medication with him.