As a recovering alcoholic myself with some PTSD in my background I have to say that if he has made an effort to get professional help I applaud him.
As a wife of a first responder, and a resident of the same area where this tragedy occurred, why do you not see a need for recovery for yourself as well? This kind of tragedy isn't something that just goes away - it has real and lasting effects on you, your family, your community, the law enforcement and medical community, etc. I am sure your husband is not the only one who was deeply and forevermore changed. Aren't there trauma recovery groups you could plug in to in your area? Surely the local hospitals have had lots of PTSD and addiction reported in response to this type event.
I drank for many years to escape and numb out my own trauma. It is possible to heal from it but it might take more than one rehab and a little follow-up, though. It may take some long-term marriage and individual counseling for each of you and it definitely will mean you coming to grips with your own feelings about the event and the effect it had on your family. This isn't some small thing that can be forgotten. It's going to take years, not weeks to recover. Mine took decades. That doesn't mean I didn't have a meaningful life, or that I was a dishonest and uncaring person. I just had stuff to deal with - like we all do. It didn't ruin me, it is part of who I am.