Tea is prepared after son's afternoon nap (6)
I believe the answer is:
siesta
'afternoon nap' is the definition.
(Spanish term for an afternoon nap)
'tea is prepared after son's' is the wordplay.
'prepared' is an anagram indicator.
'after' is a charade indicator (letters next to each other).
'tea'+'is'='teais'
'teais' with letters rearranged gives 'iesta'.
'iesta' after 's' is 'SIESTA'.
(Other definitions for siesta that I've seen before include "Rest of Spain" , "Catnap" , "PM snooze" , "A mid-day nap in Spain" , "Afternoon nap in Cadiz" .)