Just wondering - how bad is the break? Is he able to put pressure on the foot - is he using crutches, walking cast/boot or both? There are so many types of breaks. Did he have surgery? Does he have plates? Will he be on painkillers that cloud his vision or judgement.
Make sure he gets out and about to the grocery store etc here at home... and if you dare - send him ALONE!!! That will give him a better heads up of how he can work it. You may want the
ECV for his share of the usual storage too - he may not feel up to schleping a backpack. And not sure where you are from, but a note his cast may also get quite soft from the humidity.
Make sure to bring reusable icepacks for the fridge if you have one or large Ziplock bags for ice. Ice ON the cast is also helpful for reducing swelling.
If he will be in a boot and cast-free, and not to too much pain - the best solution for the swelling is filling a wastepaper can with ICE water and plunging your leg in up to your knee for 5 mins. Morning and Night and mid-day if in room for break. Be very careful with the foot for the next five mins - it gets so cold you cannot feel it. I'm sure he'll be in the mood to be automatically careful. REALLY helps the pain and swelling after the initial shock.
I second, he may think he can 'handle' the distance, but with crutches he also loses the use of his hands, so you will have three children.

Every puddle is an accident waiting to happen, a stroller to the good ankle or one crutch a reason to wipe out, ramps and stairs are tricky, wet floors, pop spills, food on the ground, confetti etc... not much surface area on the bottom of a crutch.
Six-weeks in he may still feel pretty punky and have a large 'dangerzone' around his leg.
Any chance he has a buddy who could join you? It would make it more fun for him, extra hands for you (even if just helping your DH) and you would feel less stressed if there are things he cannot enjoy with your family. Men can always find some way to 'hang'.
If you have
trip insurance though - I'd probably postpone six-months at least though. Or if he's not up to it, be ready to have a stand in - I know it will be hard on the kids to change. If he 'just' broke it - he may not really realize yet the implications of it. It took me a while... I was supposed to be able to put weight on mine in 6 weeks, ended up being 13 before I could and then it took about another 6 weeks before I could go crutchless IN the house... Mind you - mine was a bad break.