Dad — sort to get involved with decrepit oldies (7)

I believe the answer is:

dotards

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'decrepit oldies' is the definition.
I can't tell whether this definition defines the answer.

'dad sort to get involved' is the wordplay.
'to get involved' indicates an anagram.
'dad'+'sort'='dadsort'
'dadsort' anagrammed gives 'DOTARDS'.

'with' acts as a link.

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I've seen this clue in The Guardian.

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