If you decide to extend Grace to your husband, I would set a new rule of "NO ALCOHOL". Period.
It's not about how much you drink, it's about WHY you drink. For me, I rarely drink... unless I'm struggling and dealing with lots of thoughts, feelings, and anxiety. Then I'll drink more than I should.
Am I an alcoholic? No, BUT my motivation for drinking (and smoking cigars "on occasion") is all about self-medicating.
By doing that, it means I'm avoiding dealing with what I'm experiencing, which means I'm not learning to recognize my own feelings and triggers and not learning how to handle them as an adult should.
So my advice, if you extend grace, is to also up the ante.
Self-Medicating will keep him from healing. If he wants to heal, it's gotta go away.