Maybe of pensionable age, he still has to work for his money (5)

I believe the answer is:
doyen
'maybe of pensionable age he still has' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'work for his money' is the wordplay.
I cannot really understand how this works, but
'work' could be 'do' (synonyms) and 'do' is found in the answer.
'money' could be 'yen' (Japanese currency) and 'yen' is found within the answer.
No letters remain.
This explanation may well be incorrect...
'to' acts as a link.
Can you help me to learn more?
(Other definitions for doyen that I've seen before include "Senior person" , "Most valued prof, eg" , "Group's senior member" , "Prominent group member" , "Respected field leader" .)
