Barney felt Selena's weight after she sat on his lap and almost choked him with her embrace. He didn't know what to say, Alejandro had informed her about Selena's situation and from his room which was just opposite of Selena's room, he heard her weep. That's why he asked the nurse to bring him to her room and checked her situation.
And just like what he thought, she looked so depressed. He had never seen her this sad, he didn't even know that this part existed.
He looked back and saw Killian looking at him with a serious face. There was jealousy beneath his guilty expression. He wanted to help, he really did but right now, his priority was Selena. So he parted his lips and said, "could you please leave us alone?"
Nathan and the two brothers next to him left the room. Selena wouldn't even look at them so there's no reason to stay.
When they were alone, Selena pulled from embracing Barney and stared at him.