When drunk, can siestas help? (10)
I believe the answer is:
assistance
'help?' is the definition.
('assistance' can be a synonym of 'help')
'when drunk can siestas' is the wordplay.
'when drunk' indicates an anagram (I've seen this in other clues).
'can'+'siestas'='cansiestas'
'cansiestas' is an anagram of 'ASSISTANCE'.
(Other definitions for assistance that I've seen before include "Support" , "Help" , "Aid" .)