Member of family in trouble, right to be locked in (7)
I believe the answer is:
brother
'member of family' is the definition.
(type of relative)
'trouble right to be locked in' is the wordplay.
'trouble' becomes 'bother' (synonyms).
'right' becomes 'r' (common abbreviation).
'to be locked in' is an insertion indicator.
'bother' going around 'r' is 'BROTHER'.
'in' acts as a link.
(Other definitions for brother that I've seen before include "Close relative" , "Eg, monk, friar" , "Fellow-member" , "Union member - male relative" , "Relation" .)