Paradoxically the wisdom of the ages from those who have been in your position is to stand back, let your alcoholic light the fuse and wait for the explosion that is gauranteed sooner or later if they choose to pursue the unicorn that is 'controlled drinking'
There are chapters of the AA big book, dedicated to the partners and family of the alcoholic and they are a masterclass in what to expect, how to deal with it and ultimately how to have faith that your alcoholic can and will recover if they want to.