At the time of writing, March 2019, Queensland, Australia does not have an amnesty for medicinal use of illicit cannabis.
There is some confusion that NSW has an amnesty and thus so does Queensland. However, even in NSW there is no full amnesty.
In New South Wales there is an approach for ‘compassionate access’ for patients who are terminally ill. This allows the police to make judgements and not prosecute users of cannabis for medical reasons. This approach does not apply in Queensland.
So why is there a request for an amnesty? Because some patients, and parents of patients, are using illicit drugs to treat conditions. They have found that the use of cannabis improves their quality of life and are asking for an amnesty so they can continue their use without threat of prosecution.
The reason why there is no amnesty is the concern that the use of illicit drugs from unknown sources is quite dangerous. The use of cannabis would not be part of any treatment plan overseen by a doctor. Nothing is known about their source or how they will interact with other legal drugs.
If the patient entered a medical facility the professionals there would not be able legally to use these drugs and thus treatment could not continue.
So currently in Queensland, you can’t legally grow and use your own cannabis, even for medical purposes. You should look for legal sources of the necessary drugs.