Is it always plain sailing for him? (8,6)
I believe the answer is:
ordinary seaman
'is it always plain sailing for him?' is the definition.
The definition suggests a singular noun which matches the answer.
'plain sailing for him?' is the wordplay.
'plain' becomes 'ordinary' (I've seen this before).
'sailing for him?' becomes 'seaman' (I can't justify this - if you can you should believe this answer much more).
'ordinary'+'seaman'='ORDINARY SEAMAN'
(Other definitions for ordinary seaman that I've seen before include "Crew member" , "OS in full" , "Lowest rank of Royal Navy sailor" .)