Apple ID issue

Hello, my little boy has been gifted an old Iphone 7+ by a friend. However, we could not use it because it was linked to their Apple ID, they have kindly unlinked the Iphone on their end but the IPhone is still asking us for their apple password, which -for obvious privacy reasons- they do not want to share and they cannot pop-in to ours and enter it themselves as they have relocated to Scotland (hence the gift to get rid of the phone!). What can we do?