The best thing to do with individuals who are deeply angry about the results of this election is to leave them alone and don't challenge them seeker. If you have a Facebook account don't express any political opinions.

Your friend is clearly so angry right now that unless he gains support in his anger he doesn't want to interact. As "his" friend all you can do is give him some space and don't engage him with any political discussions unless you are willing to offer comfort in his extreme disappointment at this outcome.