You could send them to Peru, for 7-10 day Ayahuasca retreats. It's very effective in helping with addiction, and largely, the underlying mental health issues that lead to addictions. The guidance given by the spiritual leaders of the retreats is every bit as good as what you can get with a rehab counselor, if not better.
Overall cost, including transportation would be a few thousand dollars, which is pretty cheap, comparatively speaking.
Here's why Canada won't do that, though - All the conservative whiners who will complain about addicts getting a free trip to Peru.
Alternatively, train the staff, legalize Aya and open up retreats in Canada.