I don't think he does either, especially since his birthday can't be pinned with too much, if any, accuracy. I don't think it matters if or when you celebrate the birth of Jesus, and I think it's surely a faithful act of worship if you so choose to celebrate Christmas as the birth of the Savior.
The whole discussion over Christmas is borderline absurd.
Right. Nobody is bowing down to the pine trees in their homes; nobody is offering them sacrifices or offerings. Nobody is worshiping Frosty the Snowman, Rudolph, St. Nicholas, Jack Frost, Mr. Scrooge, Little Jack Horner, or Ralphie (though he has become TBS' form of Christmas liturgy).
For us, Christmas is a time when my family actually gets together (we're literally spread across the nation and world) and spend some rare quality time together. My mother does decorate the house a little. We do have a fake tree in a room. The cats like playing in it. We attend a Christmas Eve service where the familiar verses from Luke are read and we sing songs to and about our Lord and Savior. We spend Christmas day mostly hanging out and pigging out followed by heavy napping.
Oh, if anyone could only stop all that heresey, paganism, and idolatry from taking place! It's absurd on it's face to call any of this idolatry or pagan. And to complain about the origins of some of our holiday practices is a blatant genetic fallacy and as such shouldn't be entertained by any rational person. Whatever their origins may or may not have been, the observed practices are what they are now.
Also interesting, a large chunk of my family observes Christmas on Jan 6th. But this begins to blow holes in pagan origin claims that I will save for another post.