My guess he used Blackra1n to JB, isnstalled blacksn0w and deleted the blackra1n app...
Why do you want cydia? ill be blunt, you dont seem to have much of a clue on the phone, you can really bugger it up with cydia if you dont know what you are doing.
I have a mate who i have unlocked for, and i done the same (deleted BRa1n after unlock) so he cannot use cydia, as i know he will just install random things from it and ill have to fix it again for him.
What Firmware are you running? (Settings>General>About off the top of my head)
EDIT > First post was asking if he needs cydia.. you dont need it, just set up an itunes account on your phone or through itunes.