Daniel almost drops his phone when it rings. He answers the strange number: it's Natasha. When she explains that Charlie gave her his number, Daniel begins to wonder if Charlie's playing a joke on him. She explains that she just left Dae Hyun's store, and Daniel explains that he's back at the lawyer's building. He says it was the only place he thought he might find her. He apologizes for being a jerk and says that her immigration issue wasn't his business. Natasha surprises him by saying that it was his business.
Natasha's statement that her deportation is Daniel's issue is a very overt way for her to tell Daniel that she believes in their connection, as new and unusual it may be. Daniel's distrust when he hears that Charlie was involved illustrates just how isolated both brothers are from each other, given that they don't trust each other to do anything nice or to foster a positive connection.