According to Wikipedia, she and Barry have the same mother. Maya is married to an American citizen. However, I don’t give any weight to what she has to say about BO’s birth since she is 9 years younger, knows only what she’s been told, and (just guessing here) has seen only the documents that have been published for the public consumption.
This is fairly well-established. This would make them half-brother and half-sister to one another ... unless Obama was legally adopted by her father. Then they would legally be brother and sister.