Ethan feels a little lost without his sister or her friend. Or moreso in that he is used to being at parties with large crowds of friends or Esther so he's never found himself stuck alone. So it's quite calming to see someone who looks equally ucnertain of the surroundings. He's had a few drinks, but not enough to have lost sense of who he is. With a moment of awkwardness and perhaps a little bravery he gives a small wave toward the other on the dancefloor.