Father and I with close companion (6)
I believe the answer is:
friend
'companion' is the definition.
(I've seen this before)
'father and i with close' is the wordplay.
'father' becomes 'fr'.
'and' means one lot of letters go next to another.
'with' is a charade indicator (letters next to each other).
'close' becomes 'end' (I've seen this before).
'fr'+'i'+'end'='FRIEND'
(Other definitions for friend that I've seen before include "Close or intimate acquaintance" , "Pal or buddy" , "Person with whom you have a bond of mutual affection" , "Comrade for finder" , "China" .)