Continue to pay allstate and coverage is extended

if insurance terms have no specification that this car isn't covered in outside of us, most likely no such terms, s/he is fine. people rent cars or drive their own cars travelling to canada all the time, so no worries.

if s/he has immigrated to canada, i'd recommend to move the insurance to canada (i know it's only one insurance institute, run by government). saving a few hundreds in risk of inviting troubles does not worth it. think about it, how many years can s/he do this? make life simple, unload unnecessary burdens, move life on.