Hi - as you know it is possible to contract chicken pox from someone that has shingles. The crucial time is just before the blisters appear until they crust over.

So, it is possible that your kids could catch it. I personally would not bring them into contact with any other children/pregnant women or in fact anyone. Just until you can guage if they have contracted it.

You don't need to isolate yourself if you are immune and your partner /parents have immunity. Though it does need to be remembered that vaccination doesn't necessarily mean immunity. Nor does having had chicken pox as a child deem you immune. It's possible to still contract it - though I guess more likely that you won't.

Good luck with it! I hope your FIL feels better soon.