Family doctor, initially helpful (4)
I believe the answer is:
kind
'helpful' is the definition.
('kind' can be similar in meaning to 'helpful')
'family doctor initially' is the wordplay.
'family' becomes 'kin' ('kin' can be a synonym of 'family'**).
'initially' says to take the initial letters.
The initial letter of 'doctor' is 'd'.
'kin'+'d'='KIND'
(Other definitions for kind that I've seen before include "Friendly - type" , "caring" , "style" , "Friendly; class" , "Obliging" .)