Dionysos is a God of many masks. So while he is unquestionably the wine-God—meaning not only the giver of wine, but one whose spirit is in every glass we drink—that doesn’t even begin to exhaust the totality of his being. He is the God of the dramatic arts, lord of healing, prophecy, and poetry, the bringer of fertility and abundant life for all plants and animals; he presides over kingship, rules a portion of the dead, guides youths into adulthood, and blurs all gender and social distinctions.
There are a great many other things that fall under his dominion, none of which need involve alcohol and other intoxicating substances. In fact, one of his supreme roles is as the Liberator who helps us break the bonds that hold us back from living a free and authentic existence. Addiction is the complete antithesis of freedom so I think that Dionysos has a lot to offer those in recovery and his methods could prove a lot more successful than conventional treatments, which mostly deal with the symptoms but leave the root cause of the ailment untouched.
Discipline, moderation, and respect for these substances as inherently holy things are as much a part of Dionysos’ gifts to humanity as license and glorious excess. After all it was Dionysos who first taught us to water our wine and drink in a civilized, symposiatic fashion, eschewing the dangerous consequences of overindulgence. And some Orphics were complete teetotalers except on special ritual occasions so no, one does not have to be a hard drinker to be a Dionysian.
They must have respect for his gifts and I would recommend offering a token amount of wine even if the person never tastes it since wine is sacred to him and sacrifice is about offering what is pleasing to the Gods, irrespective of our own preferences. But if a person felt that that was too much and might endanger their hard-won sobriety they could always substitute grape juice or make offerings of other appropriate fruits, foods, smelly things, art, music, and the like.