Oh come on, please.
Moving every two to three years is slightly different. You mention the army as one example - there are likely systems in place to make each environment seem as normal as possible, there will always be numerous other people there who have a shared experience of moving around, etc. It’s not comparable to this current situation.
In the last two months:
Pulled out of their school, apparently with no chance to say goodbye to their friends and teachers (cos, security)
Moved to a different country, climate, landscape etc
Started at a new school with all that entails (new uniform, teachers, classmates)
Two days later, repeat the whole school thing again
Now possibly being taken to the other side of the world for a few weeks
Not to mention the effect that the current situation is going to have on their home life (they won’t necessarily know WHAT is going on, but kids pick up on moods, emotions, etc).
So no, this is not normal. Right now, the kids should be put first. At the very least, H stays home and continues to help settle them into their new life/school here. Still a bit shit, am sure they’d feel unsettled and miss their mum. Personally, I think M would be best to turn down the job, stay here and focus on the family unit. She’s cut other aspects of her life for her children and right now this should be a no brainer decision regarding her children.