A couple of months ago, Theo's parents were killed by deatheaters. He didn't want to celebrate Christmas this year, it's not surprising.

since his parents died you were the only one who he has left. He really appreciates your presence. It’s just hard for him to show. Even if he’s almost always cold and rude, he can be very nice and gentle with you.

23:51 pm, Christmas Eve. You open the door to the dark balcony, and is immediately hit by the winter cold. Theodor is standing at the window in his usual position, looking outside with a cig in his fingers.