Its up to Microsoft, they are the ones who offered it and if your conscience can live with it, I can't see why not to take it. He has a licence now, its not a win 10 one but its not like he wanting a OS completely free - he just slow in taking the offer all of us had for a year.
Its like running without activating windows 10, you can do it but whether you should or not, is another question. Microsoft don't seem so strict anymore, look at how you can easily move the OEM between hardware now, they seem to have relaxed.