Moans about Pat losing dad's spectacles (6)
I believe the answer is:
sights
'spectacles' is the definition.
(sight can mean a visual spectacle)
'moans about pat losing dad's' is the wordplay.
'moans' becomes 'sighs' (I've seen this before).
'about' is an insertion indicator.
'pat losing dad' becomes 't' (I can't explain this - if you can you should give a lot more credence to this answer).
'sighs' enclosing 't' is 'SIGHTS'.
Can you help me to learn more?
(Other definitions for sights that I've seen before include "Visual perceptions" , "Visions, views" , "they look ridiculous" , "Spectacles" , "Places of interest for tourists" .)