Danny is the elder of April's two younger brothers. In her diary April writes that he's an "asshole" and does not think he even wants to improve as a person. His exact age is unknown, but he must be younger than April because her mother reveals that Danny was pulled out of school for one semester because the parents could not afford to send him there after her father was injured. This indicates either that he (and thus also April, presumably) was being sent to a private school, or that all education in 23rd century U.S.A. is private.