[Robert] helped his brother, [Louis], study for the chemistry exam. [Kevin] did n't think his dad, [Antonio] had time to help with homework. [Antonio] was busy fixing his brother [Robert]'s truck. [Louis] went to the park with his father, [Harold].
('Kevin', 'Harold')
[Kevin] did n't think his dad, [Antonio] had time to help with homework. [Antonio] was busy fixing his brother [Robert]'s truck. [Robert] helped his brother, [Louis], study for the chemistry exam. [Louis] went to the park with his father, [Harold].
[{('Kevin', 'grandfather', 'Harold'): [('Kevin', 'father', 'Antonio'), ('Antonio', 'father', 'Harold')]}, {('Antonio', 'father', 'Harold'): [('Antonio', 'brother', 'Robert'), ('Robert', 'father', 'Harold')]}, {('Robert', 'father', 'Harold'): [('Robert', 'brother', 'Louis'), ('Louis', 'father', 'Harold')]}]
['father', 'brother', 'brother', 'father']