For him, half the dole goes in tax! (5)
I believe the answer is:
valet
'for him' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'half the dole goes in tax' is the wordplay.
'half the' means to take half the letters.
'goes in' is an insertion indicator.
'tax' becomes 'VAT' (Value-Added Tax).
'dole' cut in half is 'le'.
'le' going into 'vat' is 'VALET'.
Can you help me to learn more?
(Other definitions for valet that I've seen before include "Man's manservant" , "Batman" , "Gentleman's gentleman" , "Personal male assistant" , "Clean (a car); attendant" .)