For sleep doxylamine succinate is the best OTC sedative hypnotic if antihistamines still work for you.
Plenty of other options to induce sleep.
He's in Australia, specifically Victoria.
Either rehabs where full, someone else is forcing him to stop using (could even be for casual cannabis or drinking) or he's actual crazy or dodging charges, you just don't know with cunts on treatment orders.
First they place you under involuntary psych hold by saying your a crazy druggie at danger to themselves or others and it waives all rights. About 3/4 of the ward will be narcs. They load you up with drugs thats effects will make anyone outside write you off at a glance. When they release you they place you on a community treatment order, do what they say or back to the psych ward with you. You must be going crazy again to disagree with their orders. No treatment for underlying conditions unless you have schizophrenia or schizoaffective disorder. You can see why some of the poor cunts end up pretending to have schizo symptoms, so they can atleast pretend their getting better.