[Wayne]'s son [Robert] went to the baseball game with his sister [Lillian], who was sick.
('Lillian', 'Robert')
[Wayne]'s son [Robert] went to the baseball game with his sister [Lillian], who was sick.
[{('Lillian', 'nephew', 'Robert'): [('Lillian', 'brother', 'Wayne'), ('Wayne', 'son', 'Robert')]}]
['brother', 'son']