[John] and his brother [Douglas] went to the arcade. They had a wonderful time. [Douglas]'s father's name is [George].
('George', 'John')
[Douglas]'s father's name is [George]. [John] and his brother [Douglas] went to the arcade. They had a wonderful time.
[{('George', 'son', 'John'): [('George', 'son', 'Douglas'), ('Douglas', 'brother', 'John')]}]
['son', 'brother']