[Dennis]'s grandfather [Clarence] is going to [Dennis]'s birthday party. [Nicholas]'s son [Dennis] entered rehab for the ninth time at the age of thirty.
('Nicholas', 'Clarence')
[Nicholas]'s son [Dennis] entered rehab for the ninth time at the age of thirty. [Dennis]'s grandfather [Clarence] is going to [Dennis]'s birthday party.
[{('Nicholas', 'father', 'Clarence'): [('Nicholas', 'son', 'Dennis'), ('Dennis', 'grandfather', 'Clarence')]}]
['son', 'grandfather']