All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
Nobody can prove they have any relics from the Prophet nowadays. There are claims from some people that they still hold some of these relics but this is false and should not be believed as it is impossible. As for saying that hair grows even outside the body, this does not mean that the body from which it was taken is alive. You could say to any person who spreads such claims, “Shave some of your hair and leave it for a period if it grows this means you are still alive and if it does not grow this means you are dead!” Know also that the prophets are alive in their graves, as narrated in the Hadeeth (narration), but their life is different from the normal life we know and only Allaah The Almighty knows of its nature.
Allaah Knows best.