[Dale] and his brother [Nicholas] went to the football game together. [Clarence] took his son [Dale] to soccer practice.
('Clarence', 'Nicholas')
[Clarence] took his son [Dale] to soccer practice. [Dale] and his brother [Nicholas] went to the football game together.
[{('Clarence', 'son', 'Nicholas'): [('Clarence', 'son', 'Dale'), ('Dale', 'brother', 'Nicholas')]}]
['son', 'brother']