[John] decided to take his son, [Brent], on a ski vacation. [Lois] went on a vacation with her brother [John].
('Lois', 'Brent')
[Lois] went on a vacation with her brother [John]. [John] decided to take his son, [Brent], on a ski vacation.
[{('Lois', 'nephew', 'Brent'): [('Lois', 'brother', 'John'), ('John', 'son', 'Brent')]}]