Son crying in comprehensive (8)
I believe the answer is:
sweeping
'comprehensive' is the definition.
(I've seen this before)
'son crying' is the wordplay.
'son' becomes 's'.
'crying' becomes 'weeping' ('weep' can be a synonym of 'cry').
's'+'weeping'='SWEEPING'
'in' is the link.
(Other definitions for sweeping that I've seen before include "tidying up" , "work for Mrs Mopp" , "all-encompassing" , "clearing the mess?" , "Raising a dust" .)