This has come up a few times, and the general consensus seems to be that he is only choosing "feats from his selected combat style" when he gets them at 2,6,10,14 and 18. Otherwise he's taking normal feats with normal prereqs.
At 2nd level, a ranger must select one of TWO COMBAT STYLES to pursue:
ARCHERY
or
TWO-WEAPON FIGHTING.
He can choose FEATS FROM HIS SELECTED COMBAT STYLE, even if he does not have the normal prerequisites.
If the ranger selects ARCHERY, he can choose from the FOLLOWING LIST whenever he gains a combat style feat: Far Shot, Point Blank Shot, Precise Shot, and Rapid Shot.
----There is not a lot of wiggle room here.