no, unless wp gets raped like android and devs start doing whatever they want with it even if its unpractical(lumia 525 would die in 1-2h with "hey cortana" being forced to run on its hardware)
i think he is activating cortana by a bluetooth ear piece u know by long pressing the call answer button on the bluetooth ear piece we can activate cortana.....and he is may be spoofing as cortana was activated by his voice