Son became older, returning as artist (5)
I believe the answer is:
degas
'artist' is the definition.
(I've seen this before)
'son became older returning' is the wordplay.
'son' becomes 's'.
'became older' becomes 'aged' (I've seen this before).
'returning' says the letters should be written in reverse.
's'+'aged'='saged'
'saged' backwards is 'DEGAS'.
'as' acts as a link.
(Other definitions for degas that I've seen before include "Edgar -, Fr. artist" , "Edgar ---, ballet-dancer painter" , "Edgar ---, Fr. impressionist" , "He produced works of art" , "Edgar -, c. Nineteen-twenty Fr. painter" .)