Superb commercial inspiring daughter's older relative (8)
I believe the answer is:
granddad
'older relative' is the definition.
'granddad' can be an answer for 'relative' (granddad is a kind of relative). I'm not certain of the 'older' bit.
'superb commercial inspiring daughter's' is the wordplay.
'superb commercial' becomes 'grandad' (I can't explain this - if you can you should give a lot more credence to this answer).
'inspiring' is an insertion indicator.
'daughter' becomes 'd' (genealogical abbreviation).
'grandad' enclosing 'd' is 'GRANDDAD'.
Can you help me to learn more?
(Another definition for granddad that I've seen is " Familiar old man".)