Keeping quiet, one relative's shattered (2,6)
I believe the answer is:
'shattered' is the definition.
(I've seen this before)
'keeping quiet one relative's' is the wordplay.
'keeping' indicates putting letters inside.
'quiet' becomes 'p' (music symbol for 'piano').
'one' becomes 'i' (Roman numeral).
'relative's' becomes 'nieces' (niece is a kind of relative**).
'p' inserted inside 'inieces' is 'IN PIECES'.
(Another definition for in pieces that I've seen is " shattered".)