Plan to dismiss son and consent reluctantly (5)
I believe the answer is:
deign
'consent reluctantly' is the definition.
(as in deigning to do something)
'plan to dismiss son' is the wordplay.
'plan' becomes 'design' (synonyms).
'to dismiss' is a deletion indicator.
'son' becomes 's' (genealogical abbreviation for son).
'design' with 's' removed is 'DEIGN'.
'and' is the link.
(Other definitions for deign that I've seen before include "Be pleased" , "Seem supercilious" , "Think appropriate" , "Do something that's below one's dignity" , "Think fit" .)