Hi Mel,

Up until a few months ago I worked in a Drug and Alcohol clinic in Vic.

The fact that DH is ready to stop smoking pot is a big thing in itself. For change to be effective and long lasting, they need to be willing to make the change - regardless of the motivation. Any motivation is good.
There are many theories about the best way to stop drugs of addiction - some suggest cold turkey whilst others suggest weaning. Statistics show that weaning has a less relapse rate. However, it is widely accepted that for any changes in use to occur (whether it be cold turkey or reduction), the person needs to alter the behaviours associated with their use - this is best achieved through counselling and support. Support from family and friends as well as professionals such as a counsellor (who specialises in drugs and alcohol) or a psychologist. The counselling will help him to address any issues that may have seen him engage in this behaviour as well as give him ideas on how to cope with the withdrawal as well as how to change his behavior. Some people can withdraw and not be physically dependent on the substance but associate it with certain activities (such as smoking after a meal) and need help to change those associations of behaviour.
There are medications that can be prescribed to assist with the side effects of the withdrawal. Diazepam is one of the most commonly prescribed. Usually the medications prescribed are relaxants or sedatives.
Although the GP is a good place to start when seeking assistance with drug and alcohol (AOD) issues, many of them are ill equiped to deal with the issue or don't have enough knowledge on the topic. The best place to go is a centre that specialises in AOD. Community health centres often have these services and there are also centres specifically set up for these things. Prices vary from place to place, most seem to bulk bill (here in Vic). Try and google or use white pages to find services near you or contact your local community health centre or even local major hospital to see if they can point you in the right direction for your area. If you call the hospital, ask to speak to the Drug and Alcohol Department.

Although your husband will need a lot of support, it is important that you are also supported. I only know of one service in Vic who supports family and friends but they have a website so you could try that and see if it has details of related services in Brisbane. Google Family Drug Help and it should come up.

Hope that helps a little. Feel free to ask any questions and I will try to answer them. I may take a while to respond due to rotating roster (the life of a nurse!) but do feel free to ask Q's - here or PM.

Good Luck

MG