'King George', a soft old man's tipple (6)
I believe the answer is:
grappa
'tipple' is the definition.
(grappa is an alcoholic drink)
'king george a soft old man's' is the wordplay.
'king george' becomes 'gr' (Georgius Rex).
'soft' becomes 'p' (musical abbreviation for 'piano').
'old man' becomes 'pa' (both can mean father).
'gr'+'a'+'p'+'pa'='GRAPPA'
(Other definitions for grappa that I've seen before include "Italian brandy distilled from grape lees" , "hard stuff" , "Italian liqueur made from residue of grapes after pressing" , "Italian firewater" , "Spirit distilled from fermented grape remains" .)