Wreckage in half of Family Fortunes (7)
I believe the answer is:
flotsam
'wreckage' is the definition.
(flotsam is a kind of wreckage)
'in half of family fortunes' is the wordplay.
'in' indicates putting letters inside.
'half of' indicates taking half.
'fortunes' becomes 'lots' ('lot' can be a synonym of 'fortune').
'family' with half the letters taken is 'fam'.
'fam' placed around 'lots' is 'FLOTSAM'.
(Other definitions for flotsam that I've seen before include "Wreckage found floating" , "Shipwreck goods floating" , "The floating wreckage of a ship" , "Goods lost" , "Rubbish on sea" .)