Benefactor's tap on the head for a boy (6)
I believe the answer is:
patron
'benefactor's' is the definition.
(patron is a kind of benefactor)
'tap on the head for a boy' is the wordplay.
'tap on the head for' becomes 'pat' (I can't justify this - if you can you should believe this answer much more).
'a boy' becomes 'ron' (short for Ronald).
'pat'+'ron'='PATRON'
Can you help me to learn more?
(Other definitions for patron that I've seen before include "Financial supporter - customer" , "With help, he" , "Saint" , "Pot ran out for protector" , "Regular customer or sponsor" .)