Father is the opposite of Son. 
Pool can be used for Drown. Pill is etymologically related to Pool. you are likely to find Pill in/at/on Purse. you are likely to find Cash in/at/on Purse. 
Father <--Antonym--> Son 
Drown <--UsedFor-- Pool <--EtymologicallyRelatedTo-- Pill --AtLocation--> Purse <--AtLocation-- Cash 