

There are a bit different axes here. The tax money doesn’t directly go towards alleviating the suffering of family members of alcoholics, nor does it directly lower the effects of drunk driving. The income is a nice to have, for sure, but the stated aim is to be a “sin tax” which makes the bad thing less affordable.
Lev Grossman’s The Magicians takes a stab at this. In essence it’s basically Harry Potter meets The Rules of Attraction, but Grossman does discuss what magicians do after graduation. Public service is big, as are NGOs.