Windows XP
Windows XP
I might be mistaken but I don't think XP.iso is illegal. If he requested a product key, that would indicate piracy. However, I wouldn't rush to some unsafe site just to copy a download link. Try searching for "Windows XP 64-bit.iso" on Google. If it looks correct, you can likely get it from Microsoft's official site.
For software distribution, you must obtain clear authorization from the creators for sharing.