Body of Dad's son found in car (7)
I believe the answer is:
cadaver
'body' is the definition.
(I know that body can be written as cadaver)
'dad's son found in car' is the wordplay.
'dad's son' becomes 'dave' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'found in' means one lot of letters goes inside another.
'dave' inserted into 'car' is 'CADAVER'.
'of' acts as a link.
Can you help me to learn more?
(Other definitions for cadaver that I've seen before include "Remains of a human" , "Human corpse" , "Dead human body" , "Human body dissected by medical students" , "A kind of corpse" .)