My brother in law and sister, have gone back and forth between Australia and the U.S while waiting for the visas and stuff, but he seems to like it a lot here.
They have said things in passing but mostly he has said he would rather stay because he loves the nature where we live and enjoys the cold weather.
A big thing for him that he has expressed is having a snowy Christmas. He loves the winters in New England and in my state we are always blue and considerably more progressive than most states so we don't see a lot of the insanity you hear about in say Texas or Florida.
I think if it got like exceptionally bad they may move back but as I mentioned not sure.