Son needs help, it's stated (4)
I believe the answer is:
said
'stated' is the definition.
('say' can be a synonym of 'state')
'son needs help' is the wordplay.
'son' becomes 's' (genealogical abbreviation for son).
'needs' is a charade indicator (letters next to each other).
'help' becomes 'aid' (synonyms).
's'+'aid'='SAID'
'it's' is the link.
(Other definitions for said that I've seen before include "Spoke" , "Uttered at Suez port" , "Averred" , "Stated" , "Port ____, important site in the Suez crisis" .)