Where my family might be mourning? Not if I can help it! (4,2,4,4)
I believe the answer is:
over my dead body
'not if i can help it' is the definition.
(I've seen this before)
'where my family might be mourning?' is the wordplay.
I cannot quite see how this works, but
'my' is within the answer.
'be' could be 'body' (bodying is a kind of being) and 'body' is found in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for over my dead body that I've seen before include "Where six feet of earth shovelled" , "Where grave words may be spoken" , "Memorial might be erected here" , "No fear!" , "look for mourners here" .)