Silly not to protect it, why take a chance?
I'd cover the area inside walls over footings with insulated blankets. Just buy a few, they're not that expensive and you don't need many.
Straw makes one heck of a mess to clean up.
If he gets it poured well before the first frost, and it has 28 days to cure, protect it from what? Snow? I could see blanketing it if it gets poured late for sure, but otherwise it's a waste of time, money, and will be a huge mess in the Spring.
The only thing I can think he should do is cover it with some tarps to prevent UV damage to the ICF forms. Just to keep the sun from destroying the foam.
Buddy left his polystyrene foam insulation open to the sun for a couple years to long and had to replace it all when he went to final do the mason work on it.
Backfill is done, just filled in without compaction, still have close to 60 yards of topsoil to dress things up with next summer. Appreciate all the advice given.