One mainland Turkish friend of mine told me that Greece is welcome to it. But when the population of Istanbul joins with the population of Greece Turks will outnumber Greeks (Istanbul and the environs around the Sea of Marmara contain about 20million people - Greece has around 12 million). Which language to speak then? As he put it, it would be a relatively peaceful way for Turkey to regain its lands lost since the 1820s!!
I guess your friend doesn't know about the practices of Turkey in Cyprus then. Greek Cypriots are the legal majority in all parts of Cyprus, but apparently the Turks discovered a way around that problem.