I think that you have to play it by ear depending on your own circumstances. You will find some people for whom honesty will always be the best policy and others who will always go along with what the person they care for says, even adding details they have invented themselves to the person's 'story' . I tend to try not to go down the path of invention which, it seems, can easily get out of hand and even catch you out. Often a bit of distraction works and you don't even need to start spinning an appropriate story. But the ultimate test is what is most likely to make the person feel happy or, at least, untroubled.