Yeah, i'd agree he's spooked.
Pls don't take it as he's not listened to you, it's not that at all, Men are much more literal than us, we think about things very differently, they sidestep the detail.
This whole situation is, right now, not at all about you. He needs you to sit down with him, tell him that you'll support him no matter what, that if he's scared a bit, that's OK cos you are too, but that by talking it through together, perhaps you can both calm down a bit about it.
It's predominantly his decision as he is the one that is leading the family there, the weight of responsibility for the family's happiness is on him, and he will have to be 100% sure that he's doing the right thing by you all. You will have to believe in him and just be there to hand hold him through the decisions, calmly and rationally explaining your concerns.
I've just returned from 3yrs away, and I can categorically say that it was the biggest and most ghastly mistake of my entire life. Expat lifestyle sounds wonderful to anyone on the outside, but it can be the loneliest place on earth. Without question if I had stayed there, my DS would suffer even more than he has done already, and I'm in no doubt that my marriage would fail.
If he has second thoughts, they need to be HIS second thoughts, if you were concerned about leaving everything behind anyway, perhaps it might be for the best.
Perhaps this isn't the right opportunity for him at the moment, perhaps he'll find a different job in a different place that'd be more acceptable to you both at some point.
Support him either way, you have to just roll with the punches at the moment, i'm afraid, I know that's frustrating, but this really is his decision to make. If you make it, and he ends up turning the job down, you will be held to account.
If he does go, and either of you are in anyway concerned, it might be better to let him go for a month or so, get settled in his job, then you follow after. If he's trying to start a new job and worried about you, then that won't help.
Have you tried going on the Expat forums and asked what it's like to live in the place you're thinking of going? ExpatExchange & ExpatFocus are pretty extensive...
Good luck!