Any suggestions as to how I can help him overcome this fear or at least make the behavior more tolerable for all?
I've only had one dog which freaked out because of thunder / fireworks but if I could do it over again I'd attack the problem in a different way. I was always reactive not proactive because Mother Nature isn't at my disposal. This probably won't be practical but it is doable. Desensitize and CC your dog with equivalent triggers which you control. I'd use firecrackers, a reliable aide, distance threshold, engagement of a drive mode and of course some genuine praise when appropriate. Essentially create a similar environment but one which you control and can be proactive and DS/CC your dog.
Easier said than done but near threshold exposure coupled with a pleasurable diversion and the dog maintains is always a step in the right direction. Personally, I don't think there are any quick fixes for what you describe but formulating a long term plan is probably more practical.