One in disgrace, Mother got on with kind son (7,5)
I believe the answer is:
damaged goods
'one in disgrace' is the definition.
I don't know anything about this answer so I cannot tell whether this works.
'mother got on with kind son' is the wordplay.
'mother' becomes 'dam' (female parent of an animal).
'got on' becomes 'aged' ('age' can be a synonym of 'get on').
'with' means one lot of letters go next to another.
'kind' becomes 'good' (similar in meaning).
'son' becomes 's' (genealogical abbreviation for son).
'dam'+'aged'+'good'+'s'='DAMAGED GOODS'
Can you help me to learn more?
(Other definitions for damaged goods that I've seen before include "Inadequate type" , "Flawed individual" .)