Playwright's brother with genuine following in his own country (6)
I believe the answer is:
brecht
'playwright's' is the definition.
(Bertolt Brecht, 1898-1956)
'brother with genuine following in his own country' is the wordplay.
I cannot really understand how this works, but
'brother' could be 'br' (abbreviation in titles of monks) and 'br' is present in the answer.
'genuine' could be 'echt' (echt means genuine or authentic) and 'echt' is found within the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
(Other definitions for brecht that I've seen before include "Bertolt --, Ger. author" , "Bertolt ....., great German playwright of ''Mother Courage' '" , "Bertolt --, German poet, dramatist" , "Bertolt --, German writer" , "Berthold --, German dramatist" .)