You've been watching re-runs of THE PRISONER?
number 6 sounds like a secret agent designation , it could mean your friend was resourceful and good at knowing how to do things or getting out of a situation if your friend needed to , smartly
lt means you take dreams too seriously and that you are unaware of the "Dreams section" specifically designed for dreams on ep.
It means you watch too much "Kids Next Door"
who knows he could be number 6 on your list of friends you are afraid to lose....which could suggest you are afraid of losing this friend you have had for 5 years just saying you know