So, my first advice would be to NOT go back to the Lasik Center that said it would be ok to do the surgery practically the same week that he came out of contact lenses.
While complications from Lasik are a low percentage, when they do happen, they can immensely stressful and life altering. I was an EMT for many years and I can relate to your husbands situation - it's hard enough being an "industrial athlete" without glasses getting in the way.
From a practical point of view:
1) While you can go to work, mostly, the Monday after surgery, you have to avoid trauma to the eye for a month after surgery at least. Water also - is that practical on scene at a fire?
2) The eyes will feel uncomfortable, and incredibly dry. I was hydrating with drops every half hour for the first week - hard to do in turnout gear.
3) You cannot get exposed to MRSA for a month - does the fire department do medical calls? It would be advisable not to use a common shower area at the fire station - is that practical?
4) Maybe it's best to wait until after probation, when he can schedule extended time off, and/or has disability in case he's a part of the .0001% of people who have severe troubles, post surgery.
As for the rest, there's just so much to research - the surgeon matters, the technology matters. What diagnostic work has the surgeon done? What is their historical success rate? What is his best corrected vision attainable?
Too many serious questions need to be answered first.