One who’ll agree seeing desire to accommodate son, mother (3,3)
I believe the answer is:
yes man
'one who'll agree' is the definition.
(a yes man always agrees with authority)
'desire to accommodate son mother' is the wordplay.
'desire' becomes 'yen' (yen can mean a longing or desire).
'to accommodate' is an insertion indicator.
'son' becomes 's' (genealogical abbreviation for son).
'mother' becomes 'ma' (Ma is another word for mother or mum).
's'+'ma'='sma'
'yen' placed around 'sma' is 'YES-MAN'.
'seeing' acts as a link.
(Other definitions for yes man that I've seen before include "Sycophant of assenting kind" , "One always agreeing with a superior" , "He never dissents" , "A male sycophant" , "Sycophantic male employee" .)