Citizen .. yes; not a natural born citizen.
Yes. Natural Born.
Natural Born does not necessarily mean born in the US. My parents were in the military, I was born in West Germany. My legal status is Natural born.
I don’t know all of the specifics in this case, however, if they were living there and/or they were themselves legal citizens of the United States, there is a very good chance that this kid’s legal status is that of a “natural born” citizen.