Former family members attempt to support balls after duke’s departed (8)
I believe the answer is:
ancestry
'former family members' is the definition.
'attempt to support balls after duke's departed' is the wordplay.
I cannot really see how this works, but
'attempt' could be 'try' (I've seen this before) and 'try' is present in the answer.
This explanation may well be incorrect...
(Other definitions for ancestry that I've seen before include "Line of descendants" , "Any crest (anag.)" , "Genealogy" , "Line of forebears" , "Family tree" .)