[Joshua] went to the park with his sister [Cindy], [Cindy]'s brother, [Hugh], and [Hugh]'s son, [Michael].
('Joshua', 'Michael')
[Joshua] went to the park with his sister [Cindy], [Cindy]'s brother, [Hugh], and [Hugh]'s son, [Michael].
[{('Joshua', 'nephew', 'Michael'): [('Joshua', 'brother', 'Hugh'), ('Hugh', 'son', 'Michael')]}, {('Joshua', 'brother', 'Hugh'): [('Joshua', 'sister', 'Cindy'), ('Cindy', 'brother', 'Hugh')]}]
['sister', 'brother', 'son']