[Thomas] and his mother, [Lynn], went to the movie theater. [Lynn]'s father, [James], met them there. [Joshua] went to pick up his son [Thomas] from the baseball practice.
('Joshua', 'James')
[Joshua] went to pick up his son [Thomas] from the baseball practice. [Thomas] and his mother, [Lynn], went to the movie theater. [Lynn]'s father, [James], met them there.
[{('Joshua', 'father', 'James'): [('Joshua', 'son', 'Thomas'), ('Thomas', 'grandfather', 'James')]}, {('Thomas', 'grandfather', 'James'): [('Thomas', 'mother', 'Lynn'), ('Lynn', 'father', 'James')]}]
['son', 'mother', 'father']