Stay with mother in control (6)
I believe the answer is:
remain
'stay' is the definition.
(synonyms)
'mother in control' is the wordplay.
'mother' becomes 'ma' (ma can mean mother).
'in' is an insertion indicator.
'control' becomes 'rein' (rein is a kind of control).
'ma' placed into 'rein' is 'REMAIN'.
'with' acts as a link.
(Other definitions for remain that I've seen before include "Stay on after others have gone" , "Stay (in a place)" , "Old dance" , "Stay (in position)" , "Stay, don't go" .)