Given to addicts who have finished rehab, usually - they need to leave the strip on (their doctor or parole officer may check on it; families are told to check).
It blocks the happy-making dopamine effects of opiates, so if the person does sneak back into using, they won't get their high. It also reduces the number of dopamine receptors, IIRC, so that the person is more likely to be able to supply their own happy chemicals without opiates (over time).
There are other drugs (like methadone) that may be given to aid the person in the acute withdrawal phase (I'm sure there are others).
AM should not be needing suboxone, if he's clean in
IMO.