The quantity that he is consuming each day does not even come close to warranting a maintenance program.
I understand that you mean well, but withdrawal is always hard. There is not a magic pill to make it easy. It take will, and determination to pull it off.
The quantity of tea he is consuming is not in the high level, and tea itself, while containing a wide variety of alkaloids, is extremely diluted and relatively low dose. I would put it on par with hydrocodone, because if it was heroin-bad (as you seem to think it is), it would be illegal by now.
As I said, withdrawal is always hard, but not because of the physical withdrawal. The emotional energy required to get and stay clean is more than you will expend to do anything else, the withdrawal is the relatively easy part.
Supervised detox is not meant for a poppy tea addiction, it just isn't It would also be extremely difficult to find a provider that would prescribe either bupe or MMT for a poppy tea addiction. I would never suggest that supervised detox is a bad thing, but poppy tea does not have the same intense effect on the brain as more potent opiates like oxycodone or heroin.
EDIT: Let me qualify this statement. If bupe is used just for detoxing over the course of 3-7 days, that is one thing. Unfortunately, bupe is used most often as a maintenance med, which does nothing but prolong addiction and promote addictive behavior. Also, tramadol has been shown in studies to be almost as effective in minimizing withdrawal while being easier to taper down from, hence I suggested it. Substituting one addiction for another solves nothing, so in my mind, assuming he actually wants to get clean, he needs to stay away from benzos and strong opiates in general.
