Are going through that. And your poor 8 year old too that’s very scary for a child to deal with. Probably would be a very good idea to get him to some therapy ASAP if the means can be afforded or arranged for that. Anxiety attacks can sometimes be helped by change in temperature (I have them randomly and breathing in some cold or outside air can help), or having him breathe in and out slowly. I’ve also heard it can help stop them by using five senses and find something to smell, taste, touch, see, and hear. Sometimes that will help to focus and distract into stopping the panic.

I’m not sure what else would help but maybe would let him sleep with you wherever you’re staying for some comfort. I’m sure sleeping alone in a place he’s not used to might be a bit scary feeling like maybe a fire will happen again.
I’m at a loss as to what else can help him but lots of reassurance that he’s safe now and you’re there to talk about it if he wants, or he can write out his feelings if he has a hard time saying things.

Either way prayers to your family on recovering from the financial and psychological injuries any of you have suffered.