Wikipedia is not necessarily left-leaning, but you should point out to him that it's articles are constantly re-written by ordinary people, not professionals, and that it is not always accurate. It is not the Britannica. It lies. One can also be very selective with facts. You could probably use Wikipedia for your own research, too, to counter his. Also tell him that Google is in the tank with Obama (it's owner helped run his campaign), and that any search is geared toward left-leaning articles and websites. Yahoo is not much better.
Tell him to read C. S. Lewis, T.S. Eliot, Dorothy Sayers, James Hitchcock (3 Anglicans and a Catholic, all conservative) . . . sometimes the religious angle, and an appreciation for objectivity rooted in Absolute Truth (as opposed to subjectivity rooted in one’s “feelings”), can help. It may take awhile, but it is ultimately the sine qua non of most conservative thought. There also used to be a good book called The Conservative Reader. Find it.