Facial feature with spot disheartens brother expressing pain (7)
I believe the answer is:
eyebrow
'facial feature' is the definition.
(I've seen this before)
'spot disheartens brother expressing pain' is the wordplay.
'spot' becomes 'eye' (both can mean to notice or observe).
'disheartens' means to remove the middle letters (I've seen 'disheartened' mean this).
'expressing pain' becomes 'ow' ('ow' is an expression of pain).
'brother' with its middle removed is 'br'.
'eye'+'br'+'ow'='EYEBROW'
'with' acts as a link.
(Other definitions for eyebrow that I've seen before include "raising this in disapproval?" , "One of two hairy facial features" , "Penthouse, for example" , "this might be raised in surprise" , "It is raised in doubt or surprise" .)