My imagination among the many I have had concerning vampires never took me down that lane. I have imagined what it meant to be a vampire; being cold blooded, the detest and fear of the sun, the super long canines, the blood thirst, the super ability and a lot more that encapsulates the vampire character or person. Watching some of the movies could be the reason.
From all perceptions we have gained from these movies; since the most knowledge about the vampires we have had stemmed from movies and series, they are beings to be feared and dreaded, unwelcome and ones to stay far away from. All of a sudden, after such knowledge and perception, my friend is revealed as a living, moving one.
In all honesty, it won't be an easy thing to take. This is not something one should find on any day. For more reasons, vampires are said to be either extinct or non-existent in the first place. Finding out something like that would raise a concern within me, that's after the shock and the fact that I might have ran instantly for my dear life the moment I realised.
There is one thing they feed on; blood, right. And here I am, with just what that friend needs. From what we have seen, there is this insatiable thirst for blood and that is something of concern to me. So, as of first resort, I won't be getting around that friend. Staying away and observing could be the right call.
About informing others, I don't think I will be doing that, not yet at least. If this revelation about the friend being a vampire comes from themself, I think I will appreciate the honesty, sincerity and openness to me. Come to think of it, since this person is a vampire, they could just lure me somewhere and pounce on me. But coming open to me about this might suggest something more.
However, we never can tell. The lives of others beyond mine matters as well. That is where I would have issues with keeping quiet. What if others become a victim of this person's canines? Had there not been others that were victims already? These questions and more are what would go on in my mind, as I try to absorb the shock and balance the concern for my friend and the lives of others who might be victims.
Here's it, summoning courage, I would confront this friend. I would try to know how it started, what caused it and what has happened as a result of this nature? How many are they and how they survive? I have seen from “Twilight” how some clans who refused to take human blood survived on animals. Maybe that could be possible for my friend.
Otherwise, someone might have to know for the sake of the lives of others. But then, news or information like this could get people and a whole society destabilised in fear, confusion and doubts. Everyone can become a suspect, and we might become what to fear rather what we fear. So, I don't know.