[Brent] and his wife [Margaret] helped [Brent]'s father [John] with the yard work.
('Margaret', 'John')
[Brent] and his wife [Margaret] helped [Brent]'s father [John] with the yard work.
[{('Margaret', 'father-in-law', 'John'): [('Margaret', 'husband', 'Brent'), ('Brent', 'father', 'John')]}]