
The fact that the island is closer to Africa than Portugal doesnt mean anything in this case. Madeira is a vulcanic island that was totally inhabited when Portugal discovered it in 1419 and people from the mainland started to settle there. Now, portuguese people from the mainland are also a mix of several peoples that for centuries dominated Iberic Peninsula, islamic people among them (Lisbon was islamic domain till 1147).However, the greatest, most dominant genetic / ethnic influences are Celtic, Lusitanian, Roman, Visigoth and Suebian.
Enough of history lesson.
He has blood from Cape Verde. Fact. People from Cape Verde descend from a mix between portuguese settlers and african people.
Um. What?

Native Portuguese are ethnically a combination of Celts, Lusitanians, Greeks, Phoenicians, Romans, Germanic (Visigoths, Suebi, Buri), Alans, Vandals, Jews and Moors (mostly Berbers and Arabs).
Cristiano can be a mix of any of these, but I wouldn't doubt that he was as Portuguese as they come. In my opinion he and his family look just like most Portuguese people do.