I don't believe we'll need to worry about them returning anyway.
They have slim to bugger all chance getting out of ISIS controlled territory in one piece, the Australian Government will likely do what their bare minimum obligations are (i.e. likely maintain contact with their embassy in Damacus regarding any information about the children and their parents,) they'll not likely risk putting military lives or assets at risk to get them out of a hostile area and primarily, the kids need to want to leave in the first place.
They have slim to bugger all chance getting out of ISIS controlled territory in one piece, the Australian Government will likely do what their bare minimum obligations are (i.e. likely maintain contact with their embassy in Damacus regarding any information about the children and their parents,) they'll not likely risk putting military lives or assets at risk to get them out of a hostile area and primarily, the kids need to want to leave in the first place.