Some people also don't tell personal information for fear of being judged. "Out of sight is out of mind".
Apart from that, I also agree with Vash, maybe there is just nothing to tell. (Unless he is definetly avoiding specific questions).
Don't cry, don't regret and don't blame
Weak find the whip, willing find freedom
Towards the sun, carry your name
In warm hands you are given
Ask the wind for the way
Uncertainty's gone, your path will unravel
Accept all as it is and do not blame
God or the Devil
~Born to Live - Mavrik~