[Douglas] and his son [George] are playing a father-son game of basketball. [John] is waiting to go to dinner with his dad [George].
('John', 'Douglas')
[Douglas] and his son [George] are playing a father-son game of basketball. [John] is waiting to go to dinner with his dad [George].
[{('John', 'brother', 'Douglas'): [('John', 'father', 'George'), ('George', 'son', 'Douglas')]}]
['father', 'son']