He's too drunk to be calm (6)
I believe the answer is:
soothe
'be calm' is the definition.
(I've seen this in another clue)
'he's too drunk' is the wordplay.
'drunk' is an anagram indicator.
'hes'+'too'='hestoo'
'hestoo' is an anagram of 'SOOTHE'.
'to' is the link.
(Other definitions for soothe that I've seen before include "Appease" , "Cause to feel better" , "'Console, comfort (6)'" , "Calm; relieve pain" , "to settle" .)