[Wayne] played catch with his son [Jeff]. [Wayne]'s other son [Robert] does n't play baseball.
('Robert', 'Jeff')
[Wayne] played catch with his son [Jeff]. [Wayne]'s other son [Robert] does n't play baseball.
[{('Robert', 'brother', 'Jeff'): [('Robert', 'father', 'Wayne'), ('Wayne', 'son', 'Jeff')]}]
['father', 'son']