I stayed in Istanbul for a month & never managed to make the coffee taste the same as the cafes sold. Did your brother bring back a coffee pot too? Have a look at this link for a step-by-step guide:
http://www.ineedcoffee.com/04/turkishcoffee/
Enjoy,
K.
Actually, while I'm here - if anybody's ever going to Istanbul and fancies getting some coffee I can recommend a place near the Spice/Egyptian Bazaar. It was called 'Efendi' something or other, but it's along the right hand wall on the outside of the bazaar coming from the buses, near where they sell all the feta cheese and pots & pans. Finding it is half the fun & you'll smell it before you see it. The coffee just flies out of the shop & there's nothing like walking around with a packet of hot turkish coffee powder in your hand. The smell is fantastic!