Um..... First of all, Pires' mother is from Oviedo which is in Spain. His father is Portuguese which makes him a full-blooded Iberian. Also, he has family in Madrid.
Second, as a Spaniard living in France, I don't think the two cultures are terribly different. They are bother decidedly Mediterranean/Latin.
I don't think those two points can rule him out from playing in Madrid, especially since he wanted to play here because of his roots.
I also don't think the Premier league is the place for him. I think he could adapt very well to the Primera.